Back in July, Microsoft acknowledged that some Surface Pro 3 systems were seeing their battery life drop to as little as a few minutes, apparently the result of a firmware bug of some kind. The fix for this is now out (via Mary Jo Foley).

The fix is a firmware update dated 29 August that must be installed while the system is charged and plugged in. It apparently takes a couple of reboots to install. Over the course of the following few battery cycles, the batteries will return to their correct charge level. The problem is caused by something in the Surface Pro 3's firmware causing the maximum charge to be improperly reported—meaning, the SP3 mistakenly thinks the battery is full and stops accepting charge accordingly. LG and Simplo provide batteries for Microsoft's two-in-one slabs, and while users have reported issues with LG batteries, the Simplo ones appear to be the main victims of this firmware trouble.

Early reports from Microsoft's support forums suggest that, for many at least, the firmware fix does indeed do the trick.