When installing a new Sun M4000 recently, we got a bit of a surprise when we went to perform a wanboot on it. The wanboot binary downloaded, then the miniroot, and as soon as the miniroot completed, we got the following error:
krtld: load_exec: fail to expand cpu/$CPU
krtld: error during initial load/link phase
panic – boot: exitto64 returned from client program
Some searching led me to this document which is a bug report for OpenSolaris. It seems that at least one cause for this error is an out of date wanboot executable. I downloaded the latest Solaris DVD for sparc, and followed this Sun document regarding creating an updated wanboot executable and miniroot, then copied them to the web server that hosts the wanboot data by moving/renaming the old files and putting the new ones in their place. After that, we were in business.