MacBook Pro EFI Firmware Update 1.5: system confusion, what it fixes

There is some confusion regarding which MacBook Pros need EFI Firmware Update 1.5. Apple doesn't specify any particular models on its download description page, stating only:

"After the firmware is successfully applied to your Mac, your Boot ROM Version will be: MBP21.00A5.B08 or MBP31.0070.B07."

This statement led many users with Boot ROM Version strings starting in "MBP31," such as "MBP31.0070.B05," to attempt application of the update. Many, however, are greeted with a message indicating that their systems do not need the update. Exemplary reader reports:

• "I have a relatively new (January) MacBook Pro (mid 2007) 15? 2.4GHz.  I downloaded the firmware update ( MacBookProEFIUpdate1.5.dmg).  When I attempted to launch the updater I got a message indicating that my machine does not need this update.  Is it possible that this update has already been applied to newer machines?"
• "I downloaded the MacBook Pro firmware update but it said my computer did not need it.  The support document says after the firmware is updated the Boot ROM version will be MBP21.00A5.B08 or MBP31.0070.B07.  My Boot ROM version is MBP31.0070.B05.  I didn't see anything in the support documents indicating that some computers may not accept the update."

After some investigation inside the installation package, it appears that this firmware update is only applicable to the following Boot ROM Versions:

• MBP21.00A5.B01
• MBP21.00A5.B02
• MBP21.00A5.B07
• MBP31.0070.B00
• MBP31.0070.B02

You can check this number in System Profiler (located in /Applications/Utilities) under the "Hardware" tab.

Meanwhile, some users are experiencing successful installation, but noticing no change in Boot ROM Version. MacFixIt reader Robert Bondy writes:

"After running Update installer and getting a message saying the installation was successful, System Profiler shows that the old BootROM version is still installed. Rebooting did not solve the issue. Running a MacBook 3,1 with Mac OS X 10.5.2 (9C7010)"

For users who are able to install the firmware update, noticeable improvements are sparse. Some users have noticed improvements with regard to boot Camp operation -- particularly elimination of a blue color flickering problem.

Feedback? Late-breakers@macfixit.com.

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