So I just upgraded to iPhone 1.1.4 using ZiPhone 2.5 and everything seems to be working as expected until I tried Mail. It just opens and closes! One solution that was confirmed to be working is to restore back to 1.1.4 through iTunes, let ZiPhone do its magic again, and in iTunes, instead of selecting to backup from your previous iPhone select New. That should only take 10 mins but it means re-syncing data and re-installing apps again. Luckily, I found an easy fix.
1) Download OpenSHH in iPhone (make sure it’s ON by using Services or Boss Prefs).
2) Open Fugu on your Mac and connect to your iPhone.
3) You may get an error message “Warning: Remote Host Identification Has Changed”. If so, you won’t be able to connect. If not, skip to step 7.
4) On your Mac, click on the User/Home folder and hit CMD+Shift+G and type “.ssh”.
5) Delete the “known host” file.
6) Go back to Fugu and connect to your iPhone.
7) Go to var/mobile/Library/Mail.
8) Right click on Mail to set the permission to 777 or simply check all selection boxes.
You should now be able to open Mail on your iPhone!