Pretty sure I messed up. I didn't see your post till after all of this, but I downgraded to 3.55 cfw, updated to Rebug 4.75 and spoofed to 4.76, but kept getting a sign-in error so I assumed I must have installed i incorrectly or something, so I went back to 4.50 PS3ITA, and I'm still getting error code 80710A06 upon signing in. Any clue as of why I'm getting this?

If you're on PS3ita 4.50 you need to downgrade to DEX 3.55 then install Rebug 4.75.3 D REX

you dont have to downgrade you can just install rebug straight over it thats what i did

i did it just to be safe, i know i did that once and gave me update loop