The 1.5 Cupcake update for the G1 is a major effort by T-Mobile to keep its original Android powered handset competitive as new devices prepare for launch.

The SDK went out to developers a short while back, with an announcement that end-users could expect the update during May. It seems T-Mobile is a little ahead of schedule, however, as reports are filtering onto the internet that Cupcake is already arriving in European territories.

The new firmware is apparently being sent over-the-air, and so far seems to be installing quickly and without fuss.

The new Cupcake software promises video recording, an onscreen touch keyboard, orientation auto-sensing and a major overhaul of the user interface.

The first reports of users receiving the OTA update began yesterday, so G1 users should all be seeing Cupcake arrive within the next few days.