Upgrae iphone 4 on 5.0.1?

hi frens!

have iphone 4 firmware 4.3.5 , bb 04.10, please suggest me how upgrade iphone 4 on ios 5.0.1 instead of 5.1 want have unthered jailbreak? also, wan preserve basband. how can that?

 

i can't vouch it, @ own risk, this site seems give details on how can done.

 

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