Is it possible to upgrade baseband (ip4) ?

[Stinger19]

Long story short I have iPhone 4 with BB 1.59.00 and I want to upgrade the baseband incrementally through 2.10.04, 3.10.01 and 4.10.01 until I reach a baseband that does not have the signal/data/WiFi issues with iOS 4.3.x.

I cannot do it though because everything I try preserves the baseband!!
I have tried:
Stock 4.2.1 with iTunes cydia hosts or TU = preserves 1.59.00
Custom sn0wbreeze 4.2.1 with cydia hosts or TU = same

I think the only way to update baseband is to do an iTunes legit upgrade/restore which would put me at BB 4.10.01 but I did not really want to go all the way to that if possible.

Any methods or info about baseband updating/or signing or blocking would be great I cannot find much, just a lot of stuff about iPad 6.15.00.

I have lots of SHSH saved for 4.1 4.2.1 4.3.x etc.

Thanks.

[Stray]

Wait you want to LOSE the 1.59.00 baseband? WHy not just sell it and get a locked one?

[Stinger19]

LOL I know it sounds crazy but I have tried to keep 1.59.00 for so long now just for resale value but the signal problems are making the phone almost unusable (Voice, Data & WiFi & Battery problems, with 4.2.1 they are fine) but I don't wanna stay on 4.2.1 (at which the problems do not exist with 1.59.00).

PLUS now I am probably not going to bother selling the phone becuase I dropped it and insurance company replaced screen but the colour is off (yellow, compared side to side with factory ip4). - it's been 5 months and it has not burnt away (yellow glue issue).
PLUS my carrier (and others) o2 are supposedly FACTORY unlocking any contract phones (FOR FREE) which I did not know!!
PLUS if I sell it I can buy a Gevey sim for like £2.. if it's that important.
So I'd rather just have a working phone and get a new phone some day like iPhone 5 or Android.
- I just wanna know about this baseband thing I can't figure it out.

[Stray]

Ok. Go into tinyumbrella and uncheck set hosts to cydia. Go into itunes and then click restore. Done. I just sent a pm

[Stinger19]

I know that method, that's to current baseband right.. Is there no way to goto other basebands like 2.10.04, 3.10.01?

[Stray]

Nope. :/

[Stinger19]

Damn, ok thanks a lot!

[Stray]

No problem