DRNFFFFFFB0 error

I recently bought a PSP 1000 from ebay that has 5.50 GEN-D3 on it. I've been trying to update to the newest official firmware (to then put 6.60ME 1.6 on it) but I got a "DRNFFFFFFCD" error which I used Keycleaner to fix, but now I just get a "DRNFFFFFFB0" error instead.

Searching google I have found this:

DRNFFFFFFB0 = key 0x8 missing ta-086+ only

DRNFFFFFFAF = key 0x8 header is not "p D C L" (in hex: XX XX XX XX) - ta-086+ only to fix this, get IdStorage Manager and click and change key 08 to "cut this out because of copyright" and all zeroes after that.

I have messed around with IdStorage manager and know how to do what the site says but I'm a bit scared.

Is it safe to do this? It says ta-086+ only but I have a ta-082 motherboard in my PSP. So confusing... Don't want to fuck up my new toy.

Any help appreciated.