So you're saying that you initially installed FMCB onto your MC using a slimline PS2? What is the region code of your slimline?
PS2 Fat (PAL) SCPH-30003. I installed FMCB with chipped ps2 slim and I tried to reinstall it with another PS2 slim with FMCB.
Then you said that you reinstalled FMCB again with another slimline PS2. Again, what is that other console's region code?
I had successfully installed FMCB using my unmodded SCPH-77006 slimline console (Normal installation mode), and used that MC to boot my SCPH-39006 console (A v8 Fat PS2 without the Network Adaptor).
Remember that FMCB does not work on PS2s with a region code that is different from the region code of that FMCB installation (E.g. A console with "NTSC-J" as it's region code will not run a FMCB-installed MC that was built by a "NTSC-U" console).
When you mean the first time, do you mean that you reset your PS2 from the FMCB installer (aka. a warm boot)?
First time everything ran just fine. But after reset I couldn't run the same or another game again.
When you stated that FMCB failed after a few boots, what did you see (E.g. a black screen, no graphics whatsoever)?
And what do you mean "or another game"? FMCB can't run games by itself.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS