You can update to 4.1/4.2 from the recovery menu without a modchip if you have a retail disc with 4.1/4.2 update on it. NSMB or SMG2 have these updates, and others.
Also, don't update if your not sure it is bricked from a theme. You probably have cioscorp installed from softmii. You could try to burn and boot MMM-250.zip
I would do this first. If it boots, follow the softmod guide below using the modchip method to install HBC, bootmii, etc. This will have you update to 4.1 which would fix the theme brick and install priiloader before your down. This way, if reinstalling the system menu does not work, you still have other options.
You can try recovering with a game that has the 4.2 update. I've never had that work however it will install IOS70 and a new SM so worth a shot.
Edit: you should do everything in that exact order. It is a well thought out plan.
Originally Posted by mauifrog
and thanks for all your help ive burnt the above disc but still nothing i guess i will have to order nsmb from the states and pray it works
If you don't have a modchip then you can try the update from one of those official games however, if it doesn't work the modchip method will probably not exist anymore. The reason for this: the update will replace any existing cIOS with stubs and unpatched versions if you don't have cioscorp installed. It doesn't sound like you do since the MMM250 disc won't load. Unless your drive can't read backups.
Originally Posted by wiimanator
Just a warning however there's a decent chance the game update will work.