Apple on Wednesday unveiled three firmware updates designed to address issues with older batteries in its MacBook line of laptop computers.

The updates are aimed at the MacBook Pro, the MacBook, and the MacBook Air. In each case, Apple says, the new firmware should give fresh life to old batteries. The update "addresses a rare issue on some Apple notebooks, where a battery that has accumulated more than 1,000 charge cycles may unexpectedly shut down or stop functioning."

In each case, the firmware downloads are smaller than 1MB of memory. The MacBook must be running OS X 10.6.8, 10.7.5,  or 10.8.2 or later to be eligible for the firmware update. Each can be downloaded directly from Apple.

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