You can check if the problem is SMC related, when you manage to boot safely, go to PC-Link, and when you are in there press select and follow it with "A", this will start a check for corruption in your SMC card.
Before you do this, take out the SMC card, wipe the golden connectors with the smoothest piece of cloth you have, and blow gently inside the SMC slot of the GP32 (it worked for me this way once
)