To clarify 100%: If you have another way to boot homebrew, the FMCB installer will launch, and will even successfully install FMCB to the MC even under the 2.30 BIOS. Such an MC will work like any other FMCB MC with the same type of installation. The problem is merely with the lack of MC update check in the 2.30 BIOS. In fact, if you use Swap Magic to boot uLE from USB, and have an FMCB MC inserted, if you go to the file browser and run MISC/OSDSYS, then the hacked OSD will launch even with the 2.30 BIOS. There is just no unassisted FMCB boot on such consoles.
Chip-free/MC-free homebrew <3
FMCB 1.93 on MC for emergencies, NA
250GB HDD/FHDB 1.93/OPL 0.9.2 (GSM and non-GSM)/PS2 games, NO HDDOSD
80GB HDD/FHDB 1.93/POPStarter rev12/OPL644/GSM0.37/PS1 games, NO HDDOSD
SCPH-75001 (sitting idle, slims suck):
FMCB 1.92 on MC