Due to PROM limitations, all sun4c, sun4d, and sun4m architectures will not boot from partitions greater than 2 Gbytes. These systems will fail with the following message:
bootblk: can't find the boot program
All sun4u architectures support booting from larger partitions.
One related bug (4023466) reports a problem with re-preinstall where the boot image for large disks creates root partitions greater than 2 Gbytes. System administrators are cautioned not to use re-preinstall on sun4c, sun4d, and sun4m systems with large root disks (4 Gbytes and greater).