IOS 4.1 on iPhone 3G has broken corporate exchange sync (works on iPhone 4)

Question

At work we use iPhone Configuration Utility to setup corporate exchange activesync account for VIP and IT users. Our configuration uses certificate.
The last iOS update (4.1) has broken the sync for iPhones 3G.
It still work with iPhone 4 (sorry we don't have 3GS for testing !) and it worked on iOS 4.02 on the 3G.
On the 3G iOS 4.1 Mail sync the folders of the mailbox but not the messages nor calendar and contacts.
We've tried recreating the certificate but nothing changes.
Google exchange sync still works fine.
Nothing has changed on the Exchange side (HTC phones are syncing well)
Does anybody has the same problem ? and howto fix it ?
The following log was captured on the iPhone Configuration Utility on a 3G iPhone :
Fri Sep 17 11:01:37 iPhone MobileMail\[74] <Warning>: EAS|ASFolderItemsSyncTask failed with status: 1
Fri Sep 17 11:01:37 iPhone MobileMail[74] <Warning>: error syncing folder: Error Domain=MFMessageErrorDomain Code=1042 "The operation couldn’t be completed. (MFMessageErrorDomain error 1042.)"
Fri Sep 17 11:01:37 iPhone MobileMail\[74] <Warning>: EAS|server returned null sync key for sync of folderID 1. Will erase local messages, perform full sync.
Fri Sep 17 11:01:37 iPhone MobileMail\[74] <Warning>: EAS|mail db had no sync anchor for folderID 1. Will erase local messages, perform full sync.
Fri Sep 17 11:01:37 iPhone securityd\[360] <Error>: CFReadStream domain: 12 error: 8
Fri Sep 17 11:01:38 iPhone MobileMail\[74] <Warning>: EAS|No parse rule from object <ASFolderItemsSyncResponse: Collection: (null)> for codePage 0x0 token 0x11 (CPT = 17), parseRules have keys (
14,
28
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Answer 1

Same problem here. While syncing Exchange e-mail & Contacts whether over wi-fi or 3G or Edge net, phone is basically unusable until the sync completes. I have phone set to sync e-mail every 15 minutes to save battery, but it seems that e-mail and contacts sync if you open them. So, if you open contacts to look up a phone number, scrolling becomes unresponsive, as does "selecting" a name or number, presumably until sync is complete (there are about 2,000 contacts in my directory). Seems to have started with 4.1. Likewise, the phone keypad is unresponsive until sync completes. Hit a number and nothing appears to happen, so I hit it again (only to have the number repeated several times in the display 10 or 15 seconds later once sync completes). Agree it's an apparent background priority issue. A pain in the neck.
My co-workers told me they thought quickest solution was to chuck it and get a Droid. I'm not quite to that point. Anybody know of a fix yet?