EFI loader doesn't save syslog from initial stages of booting

[KapiX]

Discovered when investigating #15379:

korli (comment 5):

this syslog is weird, 4 different boots with the first part missing.

me (comment 6):

That might be because I'm using EFI and apparently it logs only to serial:

​​https://git.haiku-os.org/haiku/tree/src/system/boot/platform/efi/debug.cpp cf. ​​https://git.haiku-os.org/haiku/tree/src/system/boot/platform/bios_ia32/debug.cpp

[waddlesplash]

Appears this was fixed in ​https://git.haiku-os.org/haiku/commit/?id=cc55d4127310370f3239556e6d232fc5a58e21f1?

[KapiX]

Admittedly my loader was built before that change, but I don't think it was fixed. As per commit message, that commit only allows to see bootloader log from the boot menu, but doesn't hand it's contents over. If I understand correctly, that would happen by copying/assigning data to debug_output, but EFI loader doesn't do that.

[waddlesplash]

Fixed in hrev55433.