Thanks for the logs, I believe we're getting somewhere here.
First of all, I don't believe your ringbuffer_reverted log actually had the right patch reverted. It contains the line "*** Pre-CBMEM console overflowed, log truncated ***" which (with that exact wording) was only introduced in https://review.coreboot.org/18301. However, I think I can see enough from here to understand what you're seeing without further logs.
first_boot looks as it should to me. It ends exactly where it's supposed to end (around "Booting from Hard Disk..."). It starts with romstage output, however that output is truncated because your pre-CBMEM console buffer isn't large enough (as the message dutifully tells you). It differs from what you might have seen before because we're now only keeping the last lines of romstage (and discarding the first ones) if the pre-CBMEM buffer is too small, whereas previously we've been keeping the first lines (and been discarding the last ones). This is a sorta intentional change. You're seeing different lines from romstage now, but you've never seen all of them anyway. The real solution is to increase CONFIG_PRERAM_CBMEM_CONSOLE_SIZE for your board until it fits (note that the max amount you can set it to may be limited by hardware, though... if it just won't fit, there's not much we can do).
third_boot looks okay for coreboot but broken at the end. I believe this is because you're running SeaBIOS and you haven't updated that to support the new format. There was a separate patch for SeaBIOS that you'll need to apply to get correct console behavior: https://review.coreboot.org/cgit/seabios.git/commit/?id=19fdcca4 (You didn't mention that you were running SeaBIOS before or I could've told you earlier.)
The -1 doesn't work right because of the log truncation. I believe I may be able to improve that situation... I'll probably CC you on a patch to test in a bit.
edit: Uploaded a patch at https://review.coreboot.org/#/c/19720, please help test it out!