Old thread, but I thought I would revive it, as I am experiencing the exact same issue and I am convinced it's the PS2 that has some kind of issue when booted off any HDD with FHDB. What brought me to this conclusion;
Using 2 PS2s - both with SATA adapters fitted:
- One booted FHDB and ran Ulaunchelf and OPL just fine (we'll call this PS2#1)
- The other one, booting FHDB just fine, but black screening when trying to launch any apps like ulaunchelf and OPL (same as the original poster) (this one we'll call PS2#2).
Troubleshooting:
- I took the HDD and adapter from the non-working PS2#2, put it in the working PS2 (PS2#1), and it booted and launched the apps just fine. Put it back in the non-working PS2#2, still didn't work.
- I took the adapter and HDD from the working PS2#1, and put it in the non-working PS2#2 - would not work - boots FHDB, but black screens on a lunching any apps like OPL and unlaunchelf.
- Used FMCB card and MX4SIO in the non-working PS2#2 - and that worked fine, ran OPL and launched games as it should.
It seems that that PS2#2 has something inherent in it that will allow FHDB to boot and get to the menu just fine, but won't launch apps from the HDD with any working HDD and adapter which have been proven to be working in another PS2.
Got me stumped.