According to SamFirmware, Samsung Electronics now offers a new firmware update to Android 2.3.5 Gingerbread for all Samsung Infuse 4G devices. The announcement was made via their Twitter account a couple of hours ago.
The update is rolling out right now, you can try to plug-in your Infuse 4G into your USB cable and connect it to PC/laptop and check from KIES software for updates. If you get prompted to update than the firmware is available please get back to us with more information once you successfully finish the update.
Update: After several complains of KIES incompatibility with the phone we decided to update this article and give you an alternative until SamFirmware clears this up to why they tweeted that news. So here are the 2.3.5 stock ROM for AT&T (you need to know how to flash ROMs to update to this version).
SamFirmware replied to us and informed me that the ROM’s are directly from KIES servers, still doesn’t solve AT&T users problems (my advice is do it manually flash the rom below with Odin if you know how if not contact a local store and ask for the update for your Infuse 4G device).
Download the rom here: I997UCKI4
Model = I997
Provider = AT&T
K = 2011
I = September
4 = Version