I just upgraded my 1.0.2 iphone to 1.1.3 using Ziphone (2.4 on OSX)

I had used the ISPF unlock and was concerned it would not work correctly with ISPF.

Steps I took

1. Restored iphone to new version (1.1.3)
2. Killed itunes and itunes helper
3. Ran ZiPhone (jailbreak and activate only)

iphone wouldn't get any signal, so looked around for signal.app then read somewhere that the ziphone unlock wouldn't harm the ISPF unlock thats already been performed. (ziphone doesn't touch the seczone). Double unlocked if you like.

4. Started ziphone and chose unlock.

Sure enough, I now have a 1.1.3 phone fully unlocked.