Restore iphone 4 to 4.2.1 question?

[randy_c]

I have an iphone4 OS 4.0.1 jailbreak really late so I only have SHSH 4.2.1 saved
I used tinyumbrella save SHSH then upgrade to 4.2.1 without changing baseband and unlock to t-mobile.
I now need to restore the firmware 4.2.1 but really want to keep the basebacnd 1.59 but as I understand reading from tinyumbrella can't restore 4.2.1 without changing baseband because apple did something with baseband check and only upgrade will work without changing baseband.
Is there a way to do it?

Thanks in advance

[iYeow]

the only way is to restore to custom fw but it is complicated and may not work. google search will help u understand better

[i.Annie]

You should probably wait for a new jb or unlock that is possibly for when 4.3 is released. Like iYeow said, it's a huge pain to try custom 4.2.1 with iPhone 4.