As described in "Installing Patches That Support Net Installs and Custom JumpStart", MU4 contains several patches that correct problems with Interactive Install and Custom JumpStart. If you installed these patches, you may back out the patches using the following command:
# patchrm path_to_OS_image/Solaris_2.7/Tools/Boot patch_id |
where patch_id is the ID of the patch to back out. See Table 2-5 and Table 2-6 for lists of patch IDs.