diff --git a/Include/Acidanthera/Library/OcAppleKernelLib.h b/Include/Acidanthera/Library/OcAppleKernelLib.h
index fb8d1239..f15fb4d5 100644
--- a/Include/Acidanthera/Library/OcAppleKernelLib.h
+++ b/Include/Acidanthera/Library/OcAppleKernelLib.h
@@ -1004,16 +1004,18 @@ KcGetKextSize (
 /**
   Apply the delta from KC header to the file's offsets.
 
-  @param[in,out] Context  The context of the KEXT to rebase.
-  @param[in]     Delta    The offset from KC header the KEXT starts at.
+  @param[in]     PrelinkedContext  Prelinked context.
+  @param[in,out] Context           The context of the KEXT to rebase.
+  @param[in]     Delta             The offset from KC header the KEXT starts at.
 
   @retval EFI_SUCCESS  The file has beem rebased successfully.
   @retval other        An error has occured.
 **/
 EFI_STATUS
 KcKextApplyFileDelta (
-  IN OUT OC_MACHO_CONTEXT  *Context,
-  IN     UINT32            Delta
+  IN     PRELINKED_CONTEXT  *PrelinkedContext,
+  IN OUT OC_MACHO_CONTEXT   *Context,
+  IN     UINT32             Delta
   );
 
 /**
diff --git a/Include/Acidanthera/Library/OcMachoLib.h b/Include/Acidanthera/Library/OcMachoLib.h
index 6800abbc..0f60a284 100644
--- a/Include/Acidanthera/Library/OcMachoLib.h
+++ b/Include/Acidanthera/Library/OcMachoLib.h
@@ -32,10 +32,11 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 /// only.  Members are not guaranteed to be sane.
 ///
 typedef struct {
-  MACH_HEADER_ANY          *MachHeader;
+  VOID                     *FileData;
   UINT32                   FileSize;
 
-  UINT32                   ContainerOffset;
+  MACH_HEADER_ANY          *MachHeader;
+  UINT32                   InnerSize;
   MACH_SYMTAB_COMMAND      *Symtab;
   MACH_NLIST_ANY           *SymbolTable;
   CHAR8                    *StringTable;
@@ -50,11 +51,12 @@ typedef struct {
 /**
   Initializes a 32-bit Mach-O Context.
 
-  @param[out] Context          Mach-O Context to initialize.
-  @param[in]  FileData         Pointer to the file's expected Mach-O header.
-  @param[in]  FileSize         File size of FileData.
-  @param[in]  ContainerOffset  The amount of Bytes the Mach-O header is offset
-                               from the base (container, e.g. KC) of the file.
+  @param[out] Context       Mach-O Context to initialize.
+  @param[in]  FileData      Pointer to the file's expected Mach-O header.
+  @param[in]  FileSize      File size of FileData.
+  @param[in]  HeaderOffset  The amount of Bytes the Mach-O header is offset from
+                            the base (container, e.g. KC) of the file.
+  @param[in]  InnerSize     The size, in Bytes, of the inner Mach-O file.
 
   @return  Whether Context has been initialized successfully.
 
@@ -64,17 +66,19 @@ MachoInitializeContext32 (
   OUT OC_MACHO_CONTEXT  *Context,
   IN  VOID              *FileData,
   IN  UINT32            FileSize,
-  IN  UINT32            ContainerOffset
+  IN  UINT32            HeaderOffset,
+  IN  UINT32            InnerSize
   );
 
 /**
   Initializes a 64-bit Mach-O Context.
 
-  @param[out] Context          Mach-O Context to initialize.
-  @param[in]  FileData         Pointer to the file's expected Mach-O header.
-  @param[in]  FileSize         File size of FileData.
-  @param[in]  ContainerOffset  The amount of Bytes the Mach-O header is offset
-                               from the base (container, e.g. KC) of the file.
+  @param[out] Context       Mach-O Context to initialize.
+  @param[in]  FileData      Pointer to the file's expected Mach-O header.
+  @param[in]  FileSize      File size of FileData.
+  @param[in]  HeaderOffset  The amount of Bytes the Mach-O header is offset from
+                            the base (container, e.g. KC) of the file.
+  @param[in]  InnerSize     The size, in Bytes, of the inner Mach-O file.
 
   @return  Whether Context has been initialized successfully.
 
@@ -84,18 +88,20 @@ MachoInitializeContext64 (
   OUT OC_MACHO_CONTEXT  *Context,
   IN  VOID              *FileData,
   IN  UINT32            FileSize,
-  IN  UINT32            ContainerOffset
+  IN  UINT32            HeaderOffset,
+  IN  UINT32            InnerSize
   );
 
 /**
   Initializes a Mach-O Context.
 
-  @param[out] Context          Mach-O Context to initialize.
-  @param[in]  FileData         Pointer to the file's expected Mach-O header.
-  @param[in]  FileSize         File size of FileData.
-  @param[in]  ContainerOffset  The amount of Bytes the Mach-O header is offset
-                               from the base (container, e.g. KC) of the file.
-  @param[in]  Is32Bit          TRUE if Mach-O is 32-bit.
+  @param[out] Context       Mach-O Context to initialize.
+  @param[in]  FileData      Pointer to the file's expected Mach-O header.
+  @param[in]  FileSize      File size of FileData.
+  @param[in]  HeaderOffset  The amount of Bytes the Mach-O header is offset from
+                            the base (container, e.g. KC) of the file.
+  @param[in]  InnerSize     The size, in Bytes, of the inner Mach-O file.
+  @param[in]  Is32Bit       TRUE if Mach-O is 32-bit.
 
   @return  Whether Context has been initialized successfully.
 
@@ -105,7 +111,8 @@ MachoInitializeContext (
   OUT OC_MACHO_CONTEXT  *Context,
   IN  VOID              *FileData,
   IN  UINT32            FileSize,
-  IN  UINT32            ContainerOffset,
+  IN  UINT32            HeaderOffset,
+  IN  UINT32            InnerSize,
   IN  BOOLEAN           Is32Bit
   );
 
@@ -120,6 +127,17 @@ MachoGetMachHeader (
   IN OUT OC_MACHO_CONTEXT  *Context
   );
 
+/**
+  Returns the size of the inner Mach-O file (otherwise, the file size).
+
+  @param[in,out] Context  Context of the Mach-O.
+
+**/
+UINT32
+MachoGetInnerSize (
+  IN OUT OC_MACHO_CONTEXT  *Context
+  );
+
 /**
   Returns the 32-bit Mach-O Header structure.
 
@@ -142,6 +160,17 @@ MachoGetMachHeader64 (
   IN OUT OC_MACHO_CONTEXT  *Context
   );
 
+/**
+  Returns the file data of the Mach-O.
+
+  @param[in,out] Context  Context of the Mach-O.
+
+**/
+VOID *
+MachoGetFileData (
+  IN OUT OC_MACHO_CONTEXT  *Context
+  );
+
 /**
   Returns the Mach-O's file size.
 
diff --git a/Library/OcAppleKernelLib/CommonPatches.c b/Library/OcAppleKernelLib/CommonPatches.c
index 267445c0..cd50dd53 100644
--- a/Library/OcAppleKernelLib/CommonPatches.c
+++ b/Library/OcAppleKernelLib/CommonPatches.c
@@ -77,7 +77,7 @@ PatchAppleCpuPmCfgLock (
 
   Count     = 0;
   Walker    = (UINT8 *)MachoGetMachHeader (&Patcher->MachContext);
-  WalkerEnd = Walker + MachoGetFileSize (&Patcher->MachContext) - mWrmsrMaxDistance;
+  WalkerEnd = Walker + MachoGetInnerSize (&Patcher->MachContext) - mWrmsrMaxDistance;
 
   //
   // Thanks to Clover developers for the approach.
@@ -254,7 +254,7 @@ PatchAppleXcpmCfgLock (
   }
 
   Last = (XCPM_MSR_RECORD *)((UINT8 *)MachoGetMachHeader (&Patcher->MachContext)
-                             + MachoGetFileSize (&Patcher->MachContext) - sizeof (XCPM_MSR_RECORD));
+                             + MachoGetInnerSize (&Patcher->MachContext) - sizeof (XCPM_MSR_RECORD));
 
   Replacements = 0;
 
@@ -381,7 +381,7 @@ PatchAppleXcpmExtraMsrs (
   }
 
   Last = (XCPM_MSR_RECORD *)((UINT8 *)MachoGetMachHeader (&Patcher->MachContext)
-                             + MachoGetFileSize (&Patcher->MachContext) - sizeof (XCPM_MSR_RECORD));
+                             + MachoGetInnerSize (&Patcher->MachContext) - sizeof (XCPM_MSR_RECORD));
 
   Replacements = 0;
 
@@ -509,7 +509,7 @@ PatchAppleXcpmForceBoost (
   }
 
   Start   = (UINT8 *)MachoGetMachHeader (&Patcher->MachContext);
-  Last    = Start + MachoGetFileSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2;
+  Last    = Start + MachoGetInnerSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2;
   Start  += EFI_PAGE_SIZE;
   Current = Start;
 
@@ -1190,7 +1190,7 @@ PatchCustomPciSerialPmio (
 
   Count     = 0;
   Walker    = (UINT8 *)MachoGetMachHeader (&Patcher->MachContext);
-  WalkerEnd = Walker + MachoGetFileSize (&Patcher->MachContext) - mInOutMaxDistance;
+  WalkerEnd = Walker + MachoGetInnerSize (&Patcher->MachContext) - mInOutMaxDistance;
 
   while (Walker < WalkerEnd) {
     if (  (Walker[0] == mSerialDevicePmioFind[0])
@@ -1385,7 +1385,7 @@ PatchPanicKextDump (
   }
 
   Last = ((UINT8 *)MachoGetMachHeader (&Patcher->MachContext)
-          + MachoGetFileSize (&Patcher->MachContext) - EFI_PAGE_SIZE);
+          + MachoGetInnerSize (&Patcher->MachContext) - EFI_PAGE_SIZE);
 
   //
   // This should work on 10.15 and all debug kernels.
@@ -1811,7 +1811,7 @@ PatchSegmentJettison (
   }
 
   Last = (UINT8 *)MachoGetMachHeader (&Patcher->MachContext)
-         + MachoGetFileSize (&Patcher->MachContext) - sizeof (EFI_PAGE_SIZE) * 2;
+         + MachoGetInnerSize (&Patcher->MachContext) - sizeof (EFI_PAGE_SIZE) * 2;
 
   Status = PatcherGetSymbolAddress (Patcher, "__ZN6OSKext19removeKextBootstrapEv", (UINT8 **)&RemoveBs);
   if (EFI_ERROR (Status) || (RemoveBs > Last)) {
@@ -2055,7 +2055,7 @@ PatchLegacyCommpage (
   ASSERT (Patcher != NULL);
 
   Start = ((UINT8 *)MachoGetMachHeader (&Patcher->MachContext));
-  Last  = Start + MachoGetFileSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2 - (Patcher->Is32Bit ? sizeof (COMMPAGE_DESCRIPTOR) : sizeof (COMMPAGE_DESCRIPTOR_64));
+  Last  = Start + MachoGetInnerSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2 - (Patcher->Is32Bit ? sizeof (COMMPAGE_DESCRIPTOR) : sizeof (COMMPAGE_DESCRIPTOR_64));
 
   //
   // This is a table of pointers to commpage entries.
@@ -2294,7 +2294,7 @@ PatchForceSecureBootScheme (
   //
 
   Last = ((UINT8 *)MachoGetMachHeader (&Patcher->MachContext)
-          + MachoGetFileSize (&Patcher->MachContext) - 64);
+          + MachoGetInnerSize (&Patcher->MachContext) - 64);
 
   Status = PatcherGetSymbolAddress (Patcher, "_img4_chip_select_effective_ap", &SelectAp);
   if (EFI_ERROR (Status) || (SelectAp > Last)) {
diff --git a/Library/OcAppleKernelLib/CpuidPatches.c b/Library/OcAppleKernelLib/CpuidPatches.c
index bbfe212b..46e06b7d 100644
--- a/Library/OcAppleKernelLib/CpuidPatches.c
+++ b/Library/OcAppleKernelLib/CpuidPatches.c
@@ -815,7 +815,7 @@ PatchKernelCpuId (
     );
 
   Start = ((UINT8 *)MachoGetMachHeader (&Patcher->MachContext));
-  Last  = Start + MachoGetFileSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2 - sizeof (mKernelCpuIdFindRelNew);
+  Last  = Start + MachoGetInnerSize (&Patcher->MachContext) - EFI_PAGE_SIZE * 2 - sizeof (mKernelCpuIdFindRelNew);
 
   //
   // Do legacy patching for 32-bit 10.7, and 10.6 and older.
diff --git a/Library/OcAppleKernelLib/KernelCollection.c b/Library/OcAppleKernelLib/KernelCollection.c
index 3ee2425d..2e73fdb7 100644
--- a/Library/OcAppleKernelLib/KernelCollection.c
+++ b/Library/OcAppleKernelLib/KernelCollection.c
@@ -565,6 +565,7 @@ KcKextIndexFixups (
   CONST MACH_SEGMENT_COMMAND_64  *FirstSegment;
   MACH_HEADER_64                 *MachHeader;
   CONST MACH_RELOCATION_INFO     *Relocations;
+  VOID                           *FileData;
   UINT32                         RelocIndex;
 
   ASSERT (Context != NULL);
@@ -616,8 +617,9 @@ KcKextIndexFixups (
   //
   // Convert all relocations to fixups.
   //
+  FileData    = MachoGetFileData (MachContext);
   Relocations = (MACH_RELOCATION_INFO *)(
-                                         (UINTN)MachHeader + DySymtab->LocalRelocationsOffset
+                                         (UINTN)FileData + DySymtab->LocalRelocationsOffset
                                          );
 
   DEBUG ((
@@ -643,14 +645,11 @@ KcGetKextSize (
   IN UINT64             SourceAddress
   )
 {
-  MACH_HEADER_64           *KcHeader;
   MACH_SEGMENT_COMMAND_64  *Segment;
 
   ASSERT (Context != NULL);
   ASSERT (Context->IsKernelCollection);
 
-  KcHeader = MachoGetMachHeader64 (&Context->PrelinkedMachContext);
-  ASSERT (KcHeader != NULL);
   //
   // Find the KC segment that contains the KEXT at SourceAddress.
   //
@@ -683,8 +682,9 @@ KcGetKextSize (
 
 EFI_STATUS
 KcKextApplyFileDelta (
-  IN OUT OC_MACHO_CONTEXT  *Context,
-  IN     UINT32            Delta
+  IN     PRELINKED_CONTEXT  *PrelinkedContext,
+  IN OUT OC_MACHO_CONTEXT   *Context,
+  IN     UINT32             Delta
   )
 {
   MACH_HEADER_64           *KextHeader;
@@ -695,6 +695,7 @@ KcKextApplyFileDelta (
   MACH_DYSYMTAB_COMMAND    *DySymtab;
   UINT32                   SectIndex;
 
+  ASSERT (PrelinkedContext != NULL);
   ASSERT (Context != NULL);
   ASSERT (Delta > 0);
 
@@ -786,9 +787,11 @@ KcKextApplyFileDelta (
 
   //
   // Update the container offset to make sure we can link against this
-  // kext later as well.
+  // kext later as well. Context->InnerSize remains unchanged and is the actual
+  // size of the kext.
   //
-  Context->ContainerOffset = Delta;
+  Context->FileData = PrelinkedContext->Prelinked;
+  Context->FileSize = PrelinkedContext->PrelinkedSize;
 
   return EFI_SUCCESS;
 }
diff --git a/Library/OcAppleKernelLib/KextPatcher.c b/Library/OcAppleKernelLib/KextPatcher.c
index ff2e80dc..382d62d5 100644
--- a/Library/OcAppleKernelLib/KextPatcher.c
+++ b/Library/OcAppleKernelLib/KextPatcher.c
@@ -155,7 +155,7 @@ PatcherInitContextFromBuffer (
   // and request PRELINK_KERNEL_IDENTIFIER.
   //
 
-  if (!MachoInitializeContext (&Context->MachContext, Buffer, BufferSize, 0, Is32Bit)) {
+  if (!MachoInitializeContext (&Context->MachContext, Buffer, BufferSize, 0, BufferSize, Is32Bit)) {
     DEBUG ((
       DEBUG_INFO,
       "OCAK: %a-bit patcher init from buffer %p %u has unsupported mach-o\n",
@@ -273,7 +273,7 @@ PatcherGetSymbolAddress (
     Index++;
   }
 
-  *Address = (UINT8 *)MachoGetMachHeader (&Context->MachContext) + Offset;
+  *Address = (UINT8 *)MachoGetFileData (&Context->MachContext) + Offset;
   return EFI_SUCCESS;
 }
 
@@ -289,7 +289,7 @@ PatcherApplyGenericPatch (
   UINT32      ReplaceCount;
 
   Base = (UINT8 *)MachoGetMachHeader (&Context->MachContext);
-  Size = MachoGetFileSize (&Context->MachContext);
+  Size = MachoGetInnerSize (&Context->MachContext);
   if (Patch->Base != NULL) {
     Status = PatcherGetSymbolAddress (Context, Patch->Base, &Base);
     if (EFI_ERROR (Status)) {
@@ -520,7 +520,7 @@ PatcherBlockKext (
   }
 
   MachBase = (UINT8 *)MachoGetMachHeader (&Context->MachContext);
-  MachSize = MachoGetFileSize (&Context->MachContext);
+  MachSize = MachoGetInnerSize (&Context->MachContext);
 
   //
   // Determine offset of kmod within file.
diff --git a/Library/OcAppleKernelLib/Link.c b/Library/OcAppleKernelLib/Link.c
index e7b63913..c290e059 100644
--- a/Library/OcAppleKernelLib/Link.c
+++ b/Library/OcAppleKernelLib/Link.c
@@ -1138,7 +1138,7 @@ InternalRelocateAndCopyRelocations (
       }
 
       if (Section32->NumRelocations > 0) {
-        Relocation = (MACH_RELOCATION_INFO *)((UINTN)MachoGetMachHeader32 (&Kext->Context.MachContext) + Section32->RelocationsOffset);
+        Relocation = (MACH_RELOCATION_INFO *)((UINTN)MachoGetFileData (&Kext->Context.MachContext) + Section32->RelocationsOffset);
         for (Index = 0; Index < Section32->NumRelocations; ++Index) {
           NextRelocation = &Relocation[Index + 1];
           //
@@ -1387,7 +1387,7 @@ InternalProcessSymbolPointers (
   IN UINT64                       LoadAddress
   )
 {
-  CONST MACH_HEADER_ANY   *MachHeader;
+  CONST VOID              *FileData;
   UINT32                  MachSize;
   CONST MACH_SECTION_ANY  *Section;
   UINT32                  NumSymbols;
@@ -1434,8 +1434,8 @@ InternalProcessSymbolPointers (
     return FALSE;
   }
 
-  MachHeader = MachoGetMachHeader (MachoContext);
-  ASSERT (MachHeader != NULL);
+  FileData = MachoGetMachHeader (MachoContext);
+  ASSERT (FileData != NULL);
   //
   // Iterate through the indirect symbol table and fill in the section of
   // symbol pointers.  There are three cases:
@@ -1446,14 +1446,14 @@ InternalProcessSymbolPointers (
   //   3) An INDIRECT_SYMBOL_ABS - prepopulated absolute symbols.  No
   //      action is required.
   //
-  Tmp = (VOID *)((UINTN)MachHeader + DySymtab->IndirectSymbolsOffset);
+  Tmp = (VOID *)((UINTN)FileData + DySymtab->IndirectSymbolsOffset);
   if (!OC_TYPE_ALIGNED (UINT32, Tmp)) {
     return FALSE;
   }
 
   SymIndices = (UINT32 *)Tmp + FirstSym;
 
-  IndirectSymPtr = (VOID *)((UINTN)MachHeader + (MachoContext->Is32Bit ? Section->Section32.Offset : Section->Section64.Offset));
+  IndirectSymPtr = (VOID *)((UINTN)FileData + (MachoContext->Is32Bit ? Section->Section32.Offset : Section->Section64.Offset));
   if (MachoContext->Is32Bit ? !OC_TYPE_ALIGNED (UINT32, IndirectSymPtr) : !OC_TYPE_ALIGNED (UINT64, IndirectSymPtr)) {
     return FALSE;
   }
@@ -1512,6 +1512,7 @@ InternalPrelinkKext (
   UINT64                     LinkEditFileOffset;
   UINT64                     LinkEditFileSize;
 
+  VOID                       *FileData;
   MACH_HEADER_ANY            *MachHeader;
   UINT32                     MachSize;
   BOOLEAN                    IsObject32;
@@ -1579,9 +1580,17 @@ InternalPrelinkKext (
   MachoContext    = &Kext->Context.MachContext;
   LinkEditSegment = Kext->LinkEditSegment;
 
+  //
+  // Kexts cannot be contained.
+  //
+  ASSERT ((VOID *)MachoGetMachHeader (MachoContext) == MachoGetFileData (MachoContext));
+  ASSERT (MachoGetInnerSize (MachoContext) == MachoGetFileSize (MachoContext));
+
   MachHeader = MachoGetMachHeader (MachoContext);
   MachSize   = MachoGetFileSize (MachoContext);
 
+  FileData = (VOID *)MachHeader;
+
   IsObject32 = Context->Is32Bit && MachHeader->Header32.FileType == MachHeaderFileTypeObject;
 
   //
@@ -1801,7 +1810,7 @@ InternalPrelinkKext (
     return EFI_LOAD_ERROR;
   }
 
-  KmodInfo = (KMOD_INFO_ANY *)((UINTN)MachHeader + (UINTN)KmodInfoOffset);
+  KmodInfo = (KMOD_INFO_ANY *)((UINTN)FileData + (UINTN)KmodInfoOffset);
 
   FirstSegment = MachoGetNextSegment (MachoContext, NULL);
   if (FirstSegment == NULL) {
@@ -1934,12 +1943,12 @@ InternalPrelinkKext (
     LinkEditSize = (SymbolTableSize + RelocationsSize + StringTableSize);
 
     CopyMem (
-      (VOID *)((UINTN)MachHeader + (UINTN)LinkEditFileOffset),
+      (VOID *)((UINTN)FileData + (UINTN)LinkEditFileOffset),
       LinkEdit,
       LinkEditSize
       );
     ZeroMem (
-      (VOID *)((UINTN)MachHeader + (UINTN)LinkEditFileOffset + LinkEditSize),
+      (VOID *)((UINTN)FileData + (UINTN)LinkEditFileOffset + LinkEditSize),
       (UINTN)(LinkEditFileSize - LinkEditSize)
       );
 
@@ -2000,11 +2009,11 @@ InternalPrelinkKext (
       // Zero out the existing symbol table, and copy our non-undefined symbols back.
       //
       ZeroMem (
-        (VOID *)((UINTN)MachHeader + Symtab->SymbolsOffset),
+        (VOID *)((UINTN)FileData + Symtab->SymbolsOffset),
         SymtabSize
         );
       CopyMem (
-        (VOID *)((UINTN)MachHeader + Symtab->SymbolsOffset),
+        (VOID *)((UINTN)FileData + Symtab->SymbolsOffset),
         SymtabLinkEdit32,
         SymtabSize2
         );
@@ -2137,7 +2146,7 @@ InternalPrelinkKext (
   // Reinitialize the Mach-O context to account for the changed __LINKEDIT
   // segment and file size.
   //
-  if (!MachoInitializeContext (MachoContext, MachHeader, MachSize, MachoContext->ContainerOffset, Context->Is32Bit)) {
+  if (!MachoInitializeContext (MachoContext, MachoContext->FileData, MachSize, 0, MachSize, Context->Is32Bit)) {
     //
     // This should never failed under normal and abnormal conditions.
     //
diff --git a/Library/OcAppleKernelLib/MkextContext.c b/Library/OcAppleKernelLib/MkextContext.c
index 9dd7b03c..042a8650 100644
--- a/Library/OcAppleKernelLib/MkextContext.c
+++ b/Library/OcAppleKernelLib/MkextContext.c
@@ -1166,7 +1166,7 @@ MkextReserveKextSize (
 
   if (Executable != NULL) {
     ASSERT (ExecutableSize > 0);
-    if (!MachoInitializeContext (&Context, Executable, ExecutableSize, 0, Is32Bit)) {
+    if (!MachoInitializeContext (&Context, Executable, ExecutableSize, 0, ExecutableSize, Is32Bit)) {
       return EFI_INVALID_PARAMETER;
     }
 
diff --git a/Library/OcAppleKernelLib/PrelinkedContext.c b/Library/OcAppleKernelLib/PrelinkedContext.c
index 722ef267..9ba976e2 100644
--- a/Library/OcAppleKernelLib/PrelinkedContext.c
+++ b/Library/OcAppleKernelLib/PrelinkedContext.c
@@ -175,9 +175,10 @@ InternalConnectExternalSymtab (
 
     if (!MachoInitializeContext64 (
            InnerContext,
-           &Buffer[Segment->FileOffset],
-           (UINT32)(BufferSize - Segment->FileOffset),
-           (UINT32)Segment->FileOffset
+           Buffer,
+           BufferSize,
+           (UINT32)Segment->FileOffset,
+           (UINT32)(BufferSize - Segment->FileOffset)
            ))
     {
       DEBUG ((
@@ -247,7 +248,7 @@ PrelinkedContextInit (
   //
   // Initialise primary context.
   //
-  if (!MachoInitializeContext (&Context->PrelinkedMachContext, Prelinked, PrelinkedSize, 0, Context->Is32Bit)) {
+  if (!MachoInitializeContext (&Context->PrelinkedMachContext, Prelinked, PrelinkedSize, 0, PrelinkedSize, Context->Is32Bit)) {
     return EFI_INVALID_PARAMETER;
   }
 
@@ -921,7 +922,7 @@ PrelinkedReserveKextSize (
 
   if (Executable != NULL) {
     ASSERT (ExecutableSize > 0);
-    if (!MachoInitializeContext (&Context, Executable, ExecutableSize, 0, Is32Bit)) {
+    if (!MachoInitializeContext (&Context, Executable, ExecutableSize, 0, ExecutableSize, Is32Bit)) {
       return EFI_INVALID_PARAMETER;
     }
 
@@ -1015,7 +1016,7 @@ PrelinkedInjectKext (
   //
   if (Executable != NULL) {
     ASSERT (ExecutableSize > 0);
-    if (!MachoInitializeContext (&ExecutableContext, (UINT8 *)Executable, ExecutableSize, 0, Context->Is32Bit)) {
+    if (!MachoInitializeContext (&ExecutableContext, (UINT8 *)Executable, ExecutableSize, 0, ExecutableSize, Context->Is32Bit)) {
       DEBUG ((DEBUG_INFO, "OCAK: Injected kext %a/%a is not a supported executable\n", BundlePath, ExecutablePath));
       return EFI_INVALID_PARAMETER;
     }
@@ -1047,7 +1048,7 @@ PrelinkedInjectKext (
       AlignedExecutableSize - ExecutableSize
       );
 
-    if (  !MachoInitializeContext (&ExecutableContext, &Context->Prelinked[KextOffset], ExecutableSize, 0, Context->Is32Bit)
+    if (  !MachoInitializeContext (&ExecutableContext, &Context->Prelinked[KextOffset], ExecutableSize, 0, ExecutableSize, Context->Is32Bit)
        || OcOverflowAddU64 (Context->PrelinkedLastLoadAddress, FileOffset, &LoadAddressOffset))
     {
       return EFI_INVALID_PARAMETER;
@@ -1184,7 +1185,7 @@ PrelinkedInjectKext (
       // ownership was transferred by InternalLinkPrelinkedKext.
       //
       KcKextIndexFixups (Context, &PrelinkedKext->Context.MachContext);
-      Status = KcKextApplyFileDelta (&PrelinkedKext->Context.MachContext, KextOffset);
+      Status = KcKextApplyFileDelta (Context, &PrelinkedKext->Context.MachContext, KextOffset);
       if (EFI_ERROR (Status)) {
         DEBUG ((
           DEBUG_WARN,
diff --git a/Library/OcAppleKernelLib/PrelinkedKext.c b/Library/OcAppleKernelLib/PrelinkedKext.c
index fa9c8136..096845dc 100644
--- a/Library/OcAppleKernelLib/PrelinkedKext.c
+++ b/Library/OcAppleKernelLib/PrelinkedKext.c
@@ -56,13 +56,14 @@ InternalCreatePrelinkedKext (
   UINT64                    VirtualKmod;
   UINT64                    SourceBase;
   UINT64                    SourceSize;
+  UINT32                    InnerSize;
   UINT64                    CalculatedSourceSize;
   UINT64                    SourceEnd;
   MACH_SEGMENT_COMMAND_ANY  *BaseSegment;
   UINT64                    KxldState;
   UINT64                    KxldOffset;
   UINT32                    KxldStateSize;
-  UINT32                    ContainerOffset;
+  UINT32                    HeaderOffset;
   BOOLEAN                   Found;
   BOOLEAN                   HasExe;
   BOOLEAN                   IsKpi;
@@ -214,9 +215,18 @@ InternalCreatePrelinkedKext (
       return NULL;
     }
 
-    ContainerOffset = 0;
+    HeaderOffset = 0;
+    InnerSize    = (UINT32)SourceSize;
     if (Prelinked->IsKernelCollection) {
-      ContainerOffset = (UINT32)SourceBase;
+      HeaderOffset = (UINT32)SourceBase;
+
+      //
+      // The Mach-O image is the entire Kernel Collection image. This is because
+      // as of macOS 13 Developer Beta 3, the inner kernel Mach-O references
+      // segments that preceed it.
+      //
+      SourceBase = 0;
+      SourceSize = Prelinked->PrelinkedSize;
     }
   }
 
@@ -230,7 +240,7 @@ InternalCreatePrelinkedKext (
 
   if (  (Prelinked != NULL)
      && HasExe
-     && !MachoInitializeContext (&NewKext->Context.MachContext, &Prelinked->Prelinked[SourceBase], (UINT32)SourceSize, ContainerOffset, Prelinked->Is32Bit))
+     && !MachoInitializeContext (&NewKext->Context.MachContext, &Prelinked->Prelinked[SourceBase], (UINT32)SourceSize, HeaderOffset, InnerSize, Prelinked->Is32Bit))
   {
     FreePool (NewKext);
     return NULL;
diff --git a/Library/OcAppleKernelLib/Vtables.c b/Library/OcAppleKernelLib/Vtables.c
index 391bbb31..9480bb93 100644
--- a/Library/OcAppleKernelLib/Vtables.c
+++ b/Library/OcAppleKernelLib/Vtables.c
@@ -497,16 +497,16 @@ InternalInitializeVtablePatchData (
   OUT    MACH_NLIST_ANY        **SolveSymbols
   )
 {
-  BOOLEAN                Result;
-  UINT32                 VtableOffset;
-  UINT32                 VtableMaxSize;
-  CONST MACH_HEADER_ANY  *MachHeader;
-  VOID                   *VtableData;
-  UINT32                 SymIndex;
-  UINT32                 EntryOffset;
-  UINT64                 FileOffset;
-  UINT32                 MaxSymbols;
-  MACH_NLIST_ANY         *Symbol;
+  BOOLEAN         Result;
+  UINT32          VtableOffset;
+  UINT32          VtableMaxSize;
+  void            *FileData;
+  VOID            *VtableData;
+  UINT32          SymIndex;
+  UINT32          EntryOffset;
+  UINT64          FileOffset;
+  UINT32          MaxSymbols;
+  MACH_NLIST_ANY  *Symbol;
 
   Result = MachoSymbolGetFileOffset (
              MachoContext,
@@ -518,10 +518,10 @@ InternalInitializeVtablePatchData (
     return FALSE;
   }
 
-  MachHeader = MachoGetMachHeader (MachoContext);
-  ASSERT (MachHeader != NULL);
+  FileData = MachoGetFileData (MachoContext);
+  ASSERT (FileData != NULL);
 
-  VtableData = (VOID *)((UINTN)MachHeader + VtableOffset);
+  VtableData = (VOID *)((UINTN)FileData + VtableOffset);
   if (MachoContext->Is32Bit ? !OC_TYPE_ALIGNED (UINT32, VtableData) : !OC_TYPE_ALIGNED (UINT64, VtableData)) {
     return FALSE;
   }
@@ -591,7 +591,6 @@ InternalPatchByVtables (
   UINT32                 MaxSize;
 
   OC_MACHO_CONTEXT        *MachoContext;
-  CONST MACH_HEADER_ANY   *MachHeader;
   UINT32                  Index;
   UINT32                  NumTables;
   UINT32                  NumEntries;
@@ -620,9 +619,6 @@ InternalPatchByVtables (
   MaxSize = Context->LinkBufferSize;
 
   MachoContext = &Kext->Context.MachContext;
-
-  MachHeader = MachoGetMachHeader (MachoContext);
-  ASSERT (MachHeader != NULL);
   //
   // Retrieve all SMCPs.
   //
diff --git a/Library/OcMachoLib/Header.c b/Library/OcMachoLib/Header.c
index fa4dff65..6723b622 100644
--- a/Library/OcMachoLib/Header.c
+++ b/Library/OcMachoLib/Header.c
@@ -30,13 +30,14 @@ MachoInitializeContext (
   OUT OC_MACHO_CONTEXT  *Context,
   IN  VOID              *FileData,
   IN  UINT32            FileSize,
-  IN  UINT32            ContainerOffset,
+  IN  UINT32            HeaderOffset,
+  IN  UINT32            InnerSize,
   IN  BOOLEAN           Is32Bit
   )
 {
   return Is32Bit ?
-         MachoInitializeContext32 (Context, FileData, FileSize, ContainerOffset) :
-         MachoInitializeContext64 (Context, FileData, FileSize, ContainerOffset);
+         MachoInitializeContext32 (Context, FileData, FileSize, HeaderOffset, InnerSize) :
+         MachoInitializeContext64 (Context, FileData, FileSize, HeaderOffset, InnerSize);
 }
 
 MACH_HEADER_ANY *
@@ -50,6 +51,28 @@ MachoGetMachHeader (
   return Context->MachHeader;
 }
 
+UINT32
+MachoGetInnerSize (
+  IN OUT OC_MACHO_CONTEXT  *Context
+  )
+{
+  ASSERT (Context != NULL);
+  ASSERT (Context->InnerSize != 0);
+
+  return Context->InnerSize;
+}
+
+VOID *
+MachoGetFileData (
+  IN OUT OC_MACHO_CONTEXT  *Context
+  )
+{
+  ASSERT (Context != NULL);
+  ASSERT (Context->FileData != NULL);
+
+  return Context->FileData;
+}
+
 UINT32
 MachoGetFileSize (
   IN OUT OC_MACHO_CONTEXT  *Context
@@ -233,17 +256,12 @@ InternalInitialiseSymtabs (
   IN     MACH_DYSYMTAB_COMMAND  *DySymtab
   )
 {
-  UINTN    MachoAddress;
+  UINTN    FileDataAddress;
   CHAR8    *StringTable;
   UINT32   FileSize;
-  UINT32   SymbolsOffset;
-  UINT32   StringsOffset;
   UINT32   OffsetTop;
   BOOLEAN  Result;
 
-  UINT32                IndirectSymbolsOffset;
-  UINT32                LocalRelocationsOffset;
-  UINT32                ExternalRelocationsOffset;
   MACH_NLIST_ANY        *SymbolTable;
   MACH_NLIST_ANY        *IndirectSymtab;
   MACH_RELOCATION_INFO  *LocalRelocations;
@@ -258,37 +276,27 @@ InternalInitialiseSymtabs (
 
   FileSize = Context->FileSize;
 
-  Result = OcOverflowSubU32 (
+  Result = OcOverflowMulAddU32 (
+             Symtab->NumSymbols,
+             Context->Is32Bit ? sizeof (MACH_NLIST) : sizeof (MACH_NLIST_64),
              Symtab->SymbolsOffset,
-             Context->ContainerOffset,
-             &SymbolsOffset
+             &OffsetTop
              );
-  Result |= OcOverflowMulAddU32 (
-              Symtab->NumSymbols,
-              Context->Is32Bit ? sizeof (MACH_NLIST) : sizeof (MACH_NLIST_64),
-              SymbolsOffset,
-              &OffsetTop
-              );
   if (Result || (OffsetTop > FileSize)) {
     return FALSE;
   }
 
-  Result = OcOverflowSubU32 (
+  Result = OcOverflowAddU32 (
              Symtab->StringsOffset,
-             Context->ContainerOffset,
-             &StringsOffset
+             Symtab->StringsSize,
+             &OffsetTop
              );
-  Result |= OcOverflowAddU32 (
-              StringsOffset,
-              Symtab->StringsSize,
-              &OffsetTop
-              );
   if (Result || (OffsetTop > FileSize)) {
     return FALSE;
   }
 
-  MachoAddress = (UINTN)Context->MachHeader;
-  StringTable  = (CHAR8 *)(MachoAddress + StringsOffset);
+  FileDataAddress = (UINTN)Context->FileData;
+  StringTable     = (CHAR8 *)(FileDataAddress + Symtab->StringsOffset);
 
   if ((Symtab->StringsSize == 0) || (StringTable[Symtab->StringsSize - 1] != '\0')) {
     return FALSE;
@@ -296,7 +304,7 @@ InternalInitialiseSymtabs (
 
   SymbolTable = NULL;
 
-  Tmp = (VOID *)(MachoAddress + SymbolsOffset);
+  Tmp = (VOID *)(FileDataAddress + Symtab->SymbolsOffset);
   if (!(Context->Is32Bit ? OC_TYPE_ALIGNED (MACH_NLIST, Tmp) : OC_TYPE_ALIGNED (MACH_NLIST_64, Tmp))) {
     return FALSE;
   }
@@ -339,22 +347,17 @@ InternalInitialiseSymtabs (
     // in their DySymtab, but it is "valid" for symbols.
     //
     if ((DySymtab->NumIndirectSymbols > 0) && (DySymtab->IndirectSymbolsOffset != 0)) {
-      Result = OcOverflowSubU32 (
+      Result = OcOverflowMulAddU32 (
+                 DySymtab->NumIndirectSymbols,
+                 Context->Is32Bit ? sizeof (MACH_NLIST) : sizeof (MACH_NLIST_64),
                  DySymtab->IndirectSymbolsOffset,
-                 Context->ContainerOffset,
-                 &IndirectSymbolsOffset
+                 &OffsetTop
                  );
-      Result |= OcOverflowMulAddU32 (
-                  DySymtab->NumIndirectSymbols,
-                  Context->Is32Bit ? sizeof (MACH_NLIST) : sizeof (MACH_NLIST_64),
-                  IndirectSymbolsOffset,
-                  &OffsetTop
-                  );
       if (Result || (OffsetTop > FileSize)) {
         return FALSE;
       }
 
-      Tmp = (VOID *)(MachoAddress + IndirectSymbolsOffset);
+      Tmp = (VOID *)(FileDataAddress + DySymtab->IndirectSymbolsOffset);
       if (!(Context->Is32Bit ? OC_TYPE_ALIGNED (MACH_NLIST, Tmp) : OC_TYPE_ALIGNED (MACH_NLIST_64, Tmp))) {
         return FALSE;
       }
@@ -363,22 +366,17 @@ InternalInitialiseSymtabs (
     }
 
     if ((DySymtab->NumOfLocalRelocations > 0) && (DySymtab->LocalRelocationsOffset != 0)) {
-      Result = OcOverflowSubU32 (
+      Result = OcOverflowMulAddU32 (
+                 DySymtab->NumOfLocalRelocations,
+                 sizeof (MACH_RELOCATION_INFO),
                  DySymtab->LocalRelocationsOffset,
-                 Context->ContainerOffset,
-                 &LocalRelocationsOffset
+                 &OffsetTop
                  );
-      Result |= OcOverflowMulAddU32 (
-                  DySymtab->NumOfLocalRelocations,
-                  sizeof (MACH_RELOCATION_INFO),
-                  LocalRelocationsOffset,
-                  &OffsetTop
-                  );
       if (Result || (OffsetTop > FileSize)) {
         return FALSE;
       }
 
-      Tmp = (VOID *)(MachoAddress + LocalRelocationsOffset);
+      Tmp = (VOID *)(FileDataAddress + DySymtab->LocalRelocationsOffset);
       if (!OC_TYPE_ALIGNED (MACH_RELOCATION_INFO, Tmp)) {
         return FALSE;
       }
@@ -387,22 +385,17 @@ InternalInitialiseSymtabs (
     }
 
     if ((DySymtab->NumExternalRelocations > 0) && (DySymtab->ExternalRelocationsOffset != 0)) {
-      Result = OcOverflowSubU32 (
+      Result = OcOverflowMulAddU32 (
+                 DySymtab->NumExternalRelocations,
+                 sizeof (MACH_RELOCATION_INFO),
                  DySymtab->ExternalRelocationsOffset,
-                 Context->ContainerOffset,
-                 &ExternalRelocationsOffset
+                 &OffsetTop
                  );
-      Result |= OcOverflowMulAddU32 (
-                  DySymtab->NumExternalRelocations,
-                  sizeof (MACH_RELOCATION_INFO),
-                  ExternalRelocationsOffset,
-                  &OffsetTop
-                  );
       if (Result || (OffsetTop > FileSize)) {
         return FALSE;
       }
 
-      Tmp = (VOID *)(MachoAddress + ExternalRelocationsOffset);
+      Tmp = (VOID *)(FileDataAddress + DySymtab->ExternalRelocationsOffset);
       if (!OC_TYPE_ALIGNED (MACH_RELOCATION_INFO, Tmp)) {
         return FALSE;
       }
diff --git a/Library/OcMachoLib/HeaderX.h b/Library/OcMachoLib/HeaderX.h
index 415a7922..4f1b32ce 100644
--- a/Library/OcMachoLib/HeaderX.h
+++ b/Library/OcMachoLib/HeaderX.h
@@ -70,17 +70,12 @@ InternalSectionIsSane (
   }
 
   if (Section->NumRelocations != 0) {
-    Result = OcOverflowSubU32 (
+    Result = OcOverflowMulAddU32 (
+               Section->NumRelocations,
+               sizeof (MACH_RELOCATION_INFO),
                Section->RelocationsOffset,
-               Context->ContainerOffset,
                &TopOffset32
                );
-    Result |= OcOverflowMulAddU32 (
-                Section->NumRelocations,
-                sizeof (MACH_RELOCATION_INFO),
-                TopOffset32,
-                &TopOffset32
-                );
     if (Result || (TopOffset32 > Context->FileSize)) {
       return FALSE;
     }
@@ -264,8 +259,8 @@ MACH_X (
         *MaxSize = MACH_X_TO_UINT32 (Segment->Size - Offset);
       }
 
-      Offset += Segment->FileOffset - Context->ContainerOffset;
-      return (VOID *)((UINTN)Context->MachHeader + (UINTN)Offset);
+      Offset += Segment->FileOffset;
+      return (VOID *)((UINTN)Context->FileData + (UINTN)Offset);
     }
   }
 
@@ -323,7 +318,14 @@ MACH_X (
   //
   // Header is valid, copy it first.
   //
-  Header     = MACH_X (MachoGetMachHeader)(Context);
+  Header = MACH_X (MachoGetMachHeader)(Context);
+
+  //
+  // Mach-O files with an offset header (e.g., inner kernel files of Kernel
+  // Collections) cannot be reasonably expanded.
+  //
+  ASSERT ((CONST VOID *)Header == Context->FileData);
+
   IsObject   = Header->FileType == MachHeaderFileTypeObject;
   Source     = (UINT8 *)Header;
   HeaderSize = sizeof (*Header) + Header->CommandsSize;
@@ -387,7 +389,7 @@ MACH_X (
     // Do not overwrite header. Header must be in the first segment, but not if we are MH_OBJECT.
     // For objects, the header size will be aligned so we'll need to shift segments to account for this.
     //
-    CopyFileOffset = Segment->FileOffset - Context->ContainerOffset;
+    CopyFileOffset = Segment->FileOffset;
     CopyFileSize   = Segment->FileSize;
     CopyVmSize     = Segment->Size;
 
@@ -465,7 +467,7 @@ MACH_X (
       CurrentDelta
       ));
 
-    if (!IsObject && (DstSegment->VirtualAddress - (SegmentOffset - Context->ContainerOffset) != FirstSegment->VirtualAddress)) {
+    if (!IsObject && (DstSegment->VirtualAddress - SegmentOffset != FirstSegment->VirtualAddress)) {
       return 0;
     }
 
@@ -896,9 +898,11 @@ MACH_X (
     OUT OC_MACHO_CONTEXT  *Context,
     IN  VOID              *FileData,
     IN  UINT32            FileSize,
-    IN  UINT32            ContainerOffset
+    IN  UINT32            HeaderOffset,
+    IN  UINT32            InnerSize
     ) {
   EFI_STATUS               Status;
+  VOID                     *MachData;
   MACH_HEADER_X            *MachHeader;
   UINTN                    TopOfFile;
   UINTN                    TopOfCommands;
@@ -910,27 +914,44 @@ MACH_X (
 
   ASSERT (FileData != NULL);
   ASSERT (FileSize > 0);
+  ASSERT (FileSize >= HeaderOffset);
   ASSERT (Context != NULL);
 
+  if (HeaderOffset == 0) {
+    ASSERT (InnerSize == FileSize);
+  }
+
+  ASSERT (FileSize >= InnerSize && FileSize - InnerSize >= HeaderOffset);
+
   TopOfFile = ((UINTN)FileData + FileSize);
   ASSERT (TopOfFile > (UINTN)FileData);
 
+  MachData = (UINT8 *)FileData + HeaderOffset;
+
+  //
+  // Inner files of Kernel Collections cannot be FAT.
+  //
+  if (HeaderOffset == 0) {
  #ifdef MACHO_LIB_32
-  Status = FatFilterArchitecture32 ((UINT8 **)&FileData, &FileSize);
+    Status = FatFilterArchitecture32 ((UINT8 **)&MachData, &FileSize);
  #else
-  Status = FatFilterArchitecture64 ((UINT8 **)&FileData, &FileSize);
+    Status = FatFilterArchitecture64 ((UINT8 **)&MachData, &FileSize);
  #endif
-  if (EFI_ERROR (Status)) {
-    return FALSE;
+    if (EFI_ERROR (Status)) {
+      return FALSE;
+    }
+
+    FileData  = MachData;
+    InnerSize = FileSize;
   }
 
   if (  (FileSize < sizeof (*MachHeader))
-     || !OC_TYPE_ALIGNED (MACH_HEADER_X, FileData))
+     || !OC_TYPE_ALIGNED (MACH_HEADER_X, MachData))
   {
     return FALSE;
   }
 
-  MachHeader = (MACH_HEADER_X *)FileData;
+  MachHeader = (MACH_HEADER_X *)MachData;
  #ifdef MACHO_LIB_32
   if (MachHeader->Signature != MACH_HEADER_SIGNATURE) {
  #else
@@ -1007,10 +1028,11 @@ MACH_X (
 
   ZeroMem (Context, sizeof (*Context));
 
-  Context->MachHeader      = (MACH_HEADER_ANY *)MachHeader;
-  Context->Is32Bit         = MachHeader->CpuType == MachCpuTypeI386;
-  Context->FileSize        = FileSize;
-  Context->ContainerOffset = ContainerOffset;
+  Context->MachHeader = (MACH_HEADER_ANY *)MachHeader;
+  Context->Is32Bit    = MachHeader->CpuType == MachCpuTypeI386;
+  Context->FileData   = FileData;
+  Context->FileSize   = FileSize;
+  Context->InnerSize  = InnerSize;
 
   return TRUE;
 }
@@ -1214,16 +1236,11 @@ MACH_X (
     return NULL;
   }
 
-  Result = MACH_X (OcOverflowSubU)(
+  Result = MACH_X (OcOverflowAddU)(
              NextSegment->FileOffset,
-             Context->ContainerOffset,
+             NextSegment->FileSize,
              &TopOfSegment
              );
-  Result |= MACH_X (OcOverflowAddU)(
-              TopOfSegment,
-              NextSegment->FileSize,
-              &TopOfSegment
-              );
   if (Result || (TopOfSegment > Context->FileSize)) {
     return NULL;
   }
@@ -1239,10 +1256,10 @@ MACH_SECTION_X *
 MACH_X (
   MachoGetNextSection
   )(
-              IN OUT OC_MACHO_CONTEXT         *Context,
-              IN     MACH_SEGMENT_COMMAND_X   *Segment,
-              IN     MACH_SECTION_X           *Section  OPTIONAL
-              ) {
+             IN OUT OC_MACHO_CONTEXT         *Context,
+             IN     MACH_SEGMENT_COMMAND_X   *Segment,
+             IN     MACH_SECTION_X           *Section  OPTIONAL
+             ) {
   ASSERT (Context != NULL);
   ASSERT (Segment != NULL);
   MACH_ASSERT_X (Context);
diff --git a/Library/OcMachoLib/Relocations.c b/Library/OcMachoLib/Relocations.c
index de82cd88..38cb0593 100644
--- a/Library/OcMachoLib/Relocations.c
+++ b/Library/OcMachoLib/Relocations.c
@@ -159,7 +159,7 @@ InternalLookupSectionRelocationByOffset (
     //
     RelocationCount = Context->Is32Bit ? Section->Section32.NumRelocations : Section->Section64.NumRelocations;
     if (RelocationCount > 0) {
-      Relocations = (MACH_RELOCATION_INFO *)(((UINTN)(Context->MachHeader))
+      Relocations = (MACH_RELOCATION_INFO *)(((UINTN)(Context->FileData))
                                              + (Context->Is32Bit ? Section->Section32.RelocationsOffset : Section->Section64.RelocationsOffset));
 
       for (Index = 0; Index < RelocationCount; Index++) {
diff --git a/Library/OcMachoLib/SymbolsX.h b/Library/OcMachoLib/SymbolsX.h
index 9b899fa4..a7d1ad21 100644
--- a/Library/OcMachoLib/SymbolsX.h
+++ b/Library/OcMachoLib/SymbolsX.h
@@ -235,7 +235,7 @@ MACH_X (
   Base   = Segment->FileOffset;
   Size   = Segment->Size;
 
-  *FileOffset = MACH_X_TO_UINT32 (Base - Context->ContainerOffset + Offset);
+  *FileOffset = MACH_X_TO_UINT32 (Base + Offset);
 
   if (MaxSize != NULL) {
     *MaxSize = MACH_X_TO_UINT32 (Size - Offset);
@@ -662,7 +662,7 @@ MACH_X (
     }
   }
 
-  *FileOffset = MACH_X_TO_UINT32 (Base - Context->ContainerOffset + Offset);
+  *FileOffset = MACH_X_TO_UINT32 (Base + Offset);
 
   if (MaxSize != NULL) {
     *MaxSize = MACH_X_TO_UINT32 (Size - Offset);
diff --git a/Utilities/TestMacho/Macho.c b/Utilities/TestMacho/Macho.c
index 444285f8..1928788d 100644
--- a/Utilities/TestMacho/Macho.c
+++ b/Utilities/TestMacho/Macho.c
@@ -37,7 +37,7 @@ FeedMacho (
 {
   OC_MACHO_CONTEXT  Context;
 
-  if (!MachoInitializeContext64 (&Context, File, Size, 0)) {
+  if (!MachoInitializeContext64 (&Context, File, Size, 0, Size)) {
     return -1;
   }