efuse/kernals newb question

[Enthrall]

well I havent been keeping up with the mod scene because I thought Id just wait until someone comes up with some good news. Well that was a mistake and now Im slightly confused. I have a console made back in 2005 its kernal is 5xxx or another. Anyway its not the kernal I can use to put linux on. My question is I cant downgrade regardless if it was manufactured back in 2005 because the efuse is burnt right?

[Arakon]

correct.
you could downgrade if you knew your cpu key, but to get the cpu key, you'd have to have gotten it before upgrading in the first place.

[Enthrall]

something else its kind of off topic but I can avoid starting another thread. I want to do some modding to my console but I dont want to void it and it was manufactured in 05. If I buy a broken one off someone for real cheap can I remedy it by re soldering the cpu and applying artic cat 5.