This one is in the grey area, although I believe that it depends on how you view the existence of FMCB:
- It's probably legal because unlike modchips that circumvent the console's regional locking and anti-piracy mechanisms to play burned/pirated games or games that weren't meant for your region, FMCB just allows you to run homebrew software and not retail games.
- It's probably illegal because like with modchips, one could be booting burned/pirated/import games with software that actually circumvent the anti-piracy and regional locking mechanism of the console, like ESR, OPL, HDLoader and PS2ESDL. BUT, this is assuming that the existence of such software here is deemed as being a tool/vessal for piracy.
- OR... it's legal because of (1), but Sony just views it as being a threat because of (2).
Your country may or may not view it as being illegal. I know that for sure, mine views modchipping as being an illegal business...
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