Microsoft has rolled out an update that fixes a bug in its Surface Pro 2 tablet, a flaw that was introduced in the company's own firmware it released in December, The Inquirer reports.

Issued on Dec 10, that firmware update was released to improve system stability and update WiFi drivers, but ultimately it ended up with a number of users reporting glitches.

It was recalled eight days later following reports of problems by Microsoft's technical support community, such as significantly reducing the tablet's battery life and changing how it went into sleep mode.

Users reported that battery power was draining faster than before, that the tablets were not fully charging or that they were not showing that they were being charged.

The firm promised an alternative patch "after the holidays", which it began rolling out to users over the weekend.

"Microsoft routinely makes small changes to internal components over the lifetime of a product, based on numerous factors including supply chain partnerships, availability, and value for our customers. With any change to hardware or software, we work to ensure that the product experience remains excellent," The Inquirer quoted Microsoft spokesperson in the UK as saying.

However, there are reports that a Microsoft U.S. spokesperson said, "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. This should have no impact on customers who had not received the December update.We are working hard to deliver the rest of the December update to those customers who had not received it prior to it being removed from distribution."

The December patch that caused the battery life and charging problems has yet to be re-issued, with users not yet able to gain access to the other intended improvements, including display tweaks, improved trackpad software and audio enhancements.