Debug boot failure when there's no output

I’m sure at one point I could boot Haiku on this setup, but it may have been before I moved over to using an NVME M2 drive. On recently nightlies (and the first beta 3 test image) I can’t get this machine to boot at all - selecting a bunch of safe mode options (safe mode, safe gfx driver, disabling everything) means I can get the icons to sit on screen with none highlighting, choosing nothing but debug output causes an instant reboot when I hit “continue booting”. I’ve not found any combination of settings that’ll show any of the on-screen debug output. Not sure where to go from here, any thoughts?

This it probably some failure in boot loader at loading kernel/drivers/settings before kernel is started. Boot splash is stored and displayed by boot loader.

Is there a way to do a ‘debug’ build of the boot loader?

It is possible to enable debug tracing in boot loader by changing #ifdef's in source code.

BIOS version of boot loader has some crash debug output, UEFI may display some crash information.

I’m on UEFI - will see if I can roll a build sometime!

After setup build environment, EFI boot loader can be compiled by jam -q haiku_loader.efi.