SOLARIS X86 DON'T BOOT BECAUSE THE BOOT ARCHIVE WAS CORRUPT.
Anyway the boot archive in solaris 10 X86 was contain kernel module and configuration file was needed for solaris to startup the system.
module /platform/i86pc/boot_archive error 3 bad or corrupt data while decompressing file
Boot up your solaris in "solaris failsafe mode", next solaris image will mount with writeable mode on "/a" mount point
sh> rm -f /a/platform/i86pc/boot_archive
sh> bootadm update-archive -R /a