With mass distribution of Windows Vista SP1 around the corner, but it seems like Microsoft now facing another hiccup. Microsoft recently acknowledges that users running a dual-boot system with Windows Vista Enterprise or Ultimate edition together with a Linux distro, and have installed the Linux bootloader into the MBR, will face problem or failure when installing the service pack.
The conflict happens because one of the prerequisite update for Windows Vista SP1, KB935509, contains an update to the Windows Vista boot loader, and when upgrading to Windows Vista SP1, the original system’s bootloader on system with BitLocker encrypted drive or encrypted boot partion, may have been replaced by open source bootloaders such as GRUB or LILO when installing Linux to dual boot with Windows Vista.
Meanwhile, KB935509 contains an update to the BitLocker feature, which must ensure data integrity when updating. Thus, after entering BitLocker PIN, BitLocker update performs a “chain of trust” integrity check on everything from the system’s boot sequence, onboard TPM chip, the MBR (Master Boot Record) and into the operating system itself. When the MBR’s bootloader been replaced with LILO or GRUB in the case of dualbooting with Linux, the integrity checks will fail and the update will abort and stop, indirectly preventing SP1 from been installed. Worse, on an encrypted boot partition, the system may not boot.
Luckily, BitLocker is a feature for only Windows Vista Ultimate and Enterprise editions. So different editions of Windows Vista which doesn’t support BitLocker feature will not be affected, as KB935509 is not required to be installed. APC also listed several workarounds that dual-boot system users can do to avoid such problems:
- If the Linux and Vista partitions are installed on the same hard drive,restore the Vista MBR, either using the Vista recovery DVD or using the MBR reinstall feature contained within EasyBCD, before installing SP1.
- If the operating systems are on different hard drives, simply change the drive boot order in the BIOS to point to the disk containing Vista first, thus bypassing the Linux bootloader on the primary disk.
- The best choice of course, is to install Linux to dualboot with Windows Vista only after installing SP1.