Microsoft has issued a Surface Pro 2 update to fix issues introduced by a December firmware release, which reduced battery life and changed how the device went into sleep mode. Microsoft had initially released a firmware fix last December, but it quickly pulled it as it casued glitches.

"This weekend we released an update that addresses the unexpected wake and battery drain behavior experienced by a small number of Surface Pro 2 customers who installed the December Windows Update," according to Microsoft. "This should have no impact on customers who had not received the December update."

Microsoft is also moving to get the new update out to the users who never ended up installing the buggy December update.