[HELP] Downgrade and unlock iphone 3g from ios 4.2.1 with ipad baseband to 3.1.3

[lucil13]

I was on ios 4.2.1 and it's very slow, so i decided to downgrade it, now i get jailbroken 3.1.3 with sn0wbreeze, but my baseband stucked at ipad baseband and i cannot downgrade it because my baseband is 5.09.. can i unlock my phone with sn0wrain? can i have a good signal? because i've already got too many problems with cydia and error 1600, and i am afraid that it will brick if i unlock it.. i've also read that iphone 3g with ipad baseband should downgrade to 3.1.2, not 3.1.3, because i am not sure now what i must do next, unlock it or i need to downgrade to 3.1.2 so that i could get good signal, and use GPS.. Please somebody let me now which one is better for me to do to get my iphone back in running, because i already stuck with this cydia and 1600 problem for almost a month and my iphone is just like an ipod touch right now..

Thanks in advance!!

[iYeow]

Put your iphone into normal dfu mode and restore to stock 3.1.3 firmware, use exit reocvery from Tiny Umbrella to kick out error 1015 and jailbreak it with Redsn0w 0.9.4 but browse to stock 3.1.2 firmware. Unlock again with Ultrasn0w.