From 1981d037c1c2f2446c24e722fa4e53617d213769 Mon Sep 17 00:00:00 2001
From: Download-Fritz <download-fritz@outlook.com>
Date: Tue, 18 Jun 2019 11:15:04 +0200
Subject: [PATCH] OcFileLib: Correct partition index

---
 Library/OcFileLib/GptPartitionEntry.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Library/OcFileLib/GptPartitionEntry.c b/Library/OcFileLib/GptPartitionEntry.c
index ceb37713..e92f17c6 100644
--- a/Library/OcFileLib/GptPartitionEntry.c
+++ b/Library/OcFileLib/GptPartitionEntry.c
@@ -574,7 +574,8 @@ OcGetGptPartitionEntry (
     return NULL;
   }
 
-  Offset = ((UINTN)HdNode->PartitionNumber * Partitions->PartitionEntrySize);
+  ASSERT (HdNode->PartitionNumber > 0);
+  Offset = ((UINTN)(HdNode->PartitionNumber - 1) * Partitions->PartitionEntrySize);
   PartEntry = (EFI_PARTITION_ENTRY *)((UINTN)Partitions->FirstEntry + Offset);
   //
   // FIXME: This causes the handle to be dangling if the device is detached.