Newer versions of FMCB/FHDB doesn't seem to work on my console.

Modchips usually affect some of the newer versions of FMCB/FHDB.

Fake network adapters also tend to affect FreeHdBoot MBR.

I installed the HDD-OSD, but FHDB switches off my HDD unit and I can't see the HDD from the browser. Why does that happen?

It means that FHDB couldn't locate a HDD-OSD installation. You're probably using a heavily-hacked copy that doesn't have its files stored in the original locations.

I have the HDD-OSD and FHDB installed properly, but I get a black screen after the "Sony Computer Entertainment" screen. Why?

To aid troubleshooting this symptom, sp193 released a diagnostic tool for identifying potential problems with the HDD unit: HDDChecker

All checks must pass, for the disk to be suitable for running FHDB. This includes the S.M.A.R.T. status. Disks that fail the S.M.A.R.T. test are about to fail, and should be replaced.

If the partition bad sector check fails, it means that your disk has been marked as having bad sectors by a filesystem driver. Using WinHIIP's scan and repair function should solve that, assuming that the bad sector(s) was remapped by the drive successfully.

Alternatively, a format uLaunchELF 4.43x_isr should solve it too, at the expense of all unbacked-up data