This reverts commit f68784c8a868b4e4aad6b97044695707ab10dad9.
This code does not seem to be stable when booting with USB flash
connected, causing erratic hangs according to @roddy20.
Delay the merge till 0.6.6 until more information is known.
Note: Previous revert was caused by a build issue, presumably with
Xcode 9.2. Anyone having further issues ensure to use supported
compilers, i.e. Xcode 12.x or similar.