Iphone 3g upgrade 4.1 to 4.2.1 ???

[qsat1]

I have an Iphone 3g JB and unlocked on 4.1 (8b117)with Ipad baseband 06.15.00. JB was done with redsnow and unlock was done with ultrasnow.

I want to know how to upgrade to 4.2.1 (8c148) and maintain JB and unlock. Is this possible to do without any issues ??

I have already saved shsh using tiny umbrella and TU shows 4.1 and 4.2.1 in the list of files for this phone.

Thanks in advance for your help

[Neil001]

You must use either snowbreeze 2.1.1 (PC)or pwnage tool (Mac) to jb your device preserve your bb and unlock with ultrasnow 1.
D/l stock iOS 4.2.1 and one of the two jb app depends on you're in PC or Mac, then proceed to create custom firm ware. Google snowbreeze 2.1.1 and it'll give good detail as to how to perform the task

[qsat1]

Thanks neil I will try that but having a hard time finding snowbreeze 2.1.1

[goofball2k]

you need snowbreeze 2.2.1. That one shouldn't be hard to find.

[qsat1]

thanks goofball just downloaded snowbreeze 2.2.1. I need to resolve a problem with my home button not working all the time making it difficult getting into DFU mode will continue after I fix that