If a board is unresponsive (no video, whether using on-chip graphics or a video card), there's nothing to be lost by attempting a Recovery BIOS installation in the hope that a confused BIOS can be convinced to return to the straight and narrow (this system died right after making what should have been a simple BIOS change, disabling network boot). I have two questions on that:
1) Does the Recovery BIOS process proceed if a user cannot see video and/or interact with the PC?
2) Does the Recovery BIOS process work with a single-step downgrade of BIOS, for example, if a board is already at the latest firmware?
I'm going to try it anyway, of course.