Earlier today Apple released MacBook Air EFI Firmware Update 2.1 which will fix the problems that the MBA has with with Thunderbolt performance and OS X Lion Recovery over the Internet
According to Apple, the update is intended to:
“resolve issues with Apple Thunderbolt Display compatibility and Thunderbolt Target Disk Mode performance on MacBook Air (mid 2011) models.”
Apple emphasizes that you must not interrupt your Mac’s power during the update lest you risk turning it into a very attractive brick. The update requires OS X Lion, which is pre-installed on affected model MacBook Airs.