Second name of this bugreport:
"First stage hangs using Bochs 2.6.8"
When I tried to run latest ReactOS build (r69216) using latest Bochs (2.6.8), I got the hang - black screen right after "Loading boot drivers".
Regress tests was pointing somewhere between r45530 (good) and r45536 (bad).
Trying to figure out the problematic changes, I found nothing interesting in this commits, except for compiler/BE version upgrade (r45535).
Due to Bochs' debug log was spammed with disk-related errors and because of ReactOS' debug log shows bugcheck 0x0000007b, disk drivers came under suspicion.
What I needed next - is name of problematic driver. And I have found it - this is uniata.sys.
When I replaced bootcd-69216-dbg.iso\reactos\system32\drivers\uniata.sys with bootcd-45530-dbg.iso\reactos\uniata.sys, installation started fine and even finished fine - here is the screenshot.
I don't know what exactly happens with this driver. Probably the source is in undefined behavior somewhere in it's code, which was masked by compiler's specific.
But what I know for sure - this problem needs to be investigated. Fix for this problem may became the fix for many similar related bugs.