A number of users who have upgraded and jailbroken 1.1.4 are reporting that the Mail application stops working properly after the upgrade and/or jailbreak is complete. These reports of a broken Mail.app come in a variety of forms. For some users, Mail crashes when they attempt to open it. For others, it simply fails to download any new messages. Still, for others, Mail crashes when attempting to read a message.
Regardless of the particular symptoms your Mail is experiencing, should your Mail.app be broken after upgrading and/or jailbreaking 1.1.4, here are some possible fixes:
Fix permissions on your mail folder
2. navigate to /var/mobile/Library/mail
3. set permissions on your mail folder to 777 (via 'chmod -R 777 *)
2. Install SyncFix (under dev 1.1.3)
Perform a Restore to fresh 1.1.4
Newest iPhone FAQs
Be sure to make sure your iPhone is fully backed up before restoring.
If you have any other methods of fixing Mail issues under 1.1.4 or other related experiences, be sure to post them here.