This is just a quick note on a positive experience with Pwnage, used it in upgrading a 1.1.2 IPSF iPhone to 1.1.4 directly. The following sequence of steps worked without problems, although I have no idea whether all the steps I did really mattered.

0) What I have is an IPSF iphone, running tmobile, using the commercial IPSF software, and the IPSF instructions to upgrade to 1.1.2.
1) I downloaded the 1.1.4 ipsw image with iTunes (by choosing the download-only option)
2) I put my iphone into DUF mode
3) using option-click on the restore button in iTunes, I restored the 1.1.4 image (with the precaution that I may want ZiPhone to unlock if Pwnage does not work)
4) restore worked, tmobile was still active, but, of course, the phone was locked
5) Now I used Pwnage according to Pwnage Help instructions -- worked fine
6) Using Pwnage, I built the custom restore ipsw image, without selecting the update of the baseband.
7) following steps 2) and 3), I restored this modified ipsw image.
8) Using iTunes, I synced my computer data, but started a NEW device, i.e., did not restore from backup.

All works perfectly fine.

Are you having to use Signal.app or anything like that?

You can use use pwnage and IPSF and it will double unlock your phone so it still has the IPSF lock and the anySIM unlock.

But if you don't unlock the baseband using BootNeuter then you will have to use signal.app.

Remmeber that BootNeuter does the actual unlocking on the phone!

i used to use Geohot's Free iPSF, but i reversed it in order to use BootNeuter. If you have a backup of your NOR, I suggest you reverse your iPSF and then use BootNeuter

You don't need to reverse it.

I am not suggesting you want to make your life more complicated but by doing that your unneccessarily risking something going wrong when you don't need to do it.

Obviously it worked for you but you didn't need to do it.

BootNeuter will happily unlock an IPSF phone without any issues.