Mine failed and after some searching I found the problem...I had used a driver cleaner app and it removed some Windows files that are apparently needed for the SP1 upgrade. I downloaded the proper files from Workaround 1 and manually moved ALL OF THEM them to the winsxs directory in Workaround 2.
Windows 7 Service Pack 1 may fail to install properly on systems which have had the Driver Sweeper utility from Phyxion run against the Windows image. You could possibly encounter errors 0x800f0a13 or 0x800f0826 in your \Windows\Logs\CBS.log file that is similar to the following:
2011-02-23 10:47:55, Error CBS SPI: Driver directory C:\Windows\System32\DriverStore\FileRepository\atiilhag.inf_amd64_neutral_951c1812f542740a is missing
2011-02-23 10:47:55, Error CBS SPI: (CSPInstall::CompatibilityApplicabilityScan:1468)Inbox Driver check failed hr=0x800f0a13
Mount your Windows installation media to a folder and manually copy the ATI files to the \Windows\winsxs directories (choosing to overwrite the files if they exist). The file names are: