I have 3GS Factory Unlocked on FW: 3.1.3 & Modem Firmware 05.12.01 with new bootrom.

Missed saving me blobs for 3.1.3 & ever since have been wary to updating to any 4.x.x reading all the issues floating around with every update.

But now wana to update my device to iOS 4.

Used TinyUmbrella-4.30.05 and could only save blobs for 4.1 & 4.3.1

Pls advice which FW version of iOS4 should I update to keeping it in Factory Unlocked state.

Also, what all should I take care before going in for the update?