The folks over at SamFirmware have managed to get their hands on the Android 2.3.4 firmware for two popular Galaxy S series phone in the United States Sprint’s Epic 4G and the T-Mobile Galaxy S 4G.

The EG22 Android 2.3.4 firmware for the Epic 4G brings an overall improvement in performance and stability of the phone. The usual lag’ associated with the Galaxy S phones are pretty much absent in this firmware. However, the GPS performance on this new firmware is wonky at best. Users reported that they were able to lock to only 2 satellites even under clear skies.

The KG4 firmware for the Galaxy S 4G also brings overall improvement in performance and stability of the phone. Sadly, both the firmware for the handsets does not include the video chat capable version of GTalk.

The sources of SamFirmware are also reporting that apparently Samsung has stopped working on firmware updates for the T-Mobile Vibrant.

The leaked firmware for the Galaxy S 4G and the Epic 4G can be downloaded from here.