help Gen5.50d to ofw 6.20 error V 9.90

[Judia21]

PSP slim 2000
So i'm trying to change the version.txt

1. Hold R To recovery menu Advance> USb flash 0 enable exit recovery
2. Press select once No Recovery menu show up on screen hold select also nothing show up
3. Try to connect to USB Somehow i cant connect my memory stick to computer it keep saying "Please wait" and I already turn off my USB Charge, my memory card can only connect it through to my USB stick.
4. Try to change my Version(ofw 5.00) through Hellcat RecoveryFlasher get Error

I haven't try with Pandora Battery yet soo any other option i can take?...Beside buying a new PSP!
Thanks