The following describes a procedure to make a SPARC CPU run faster than its set speed. I personally do NOT do this on any machine I care about, and can make absolutely no verification of how well it works, or any risks it may pose to the hardware. The only time I have witnessed this done was on a 300-MHz Ultra-II, which was able to be overclocked to around 350-MHz. I forget whether attempts to go higher stopped at the 350-MHz limit, or simply had no effect.
You will need to be at the eeprom's 'ok' prompt.
ok nvedit 0: also hidden 1: d# 123 at-speed (...where 123 is the speed you want, in MHz) 2: <Ctrl-C> ok nvstore ok setenv use-nvramrc? true ok reset-all
To read the CPU clock speed: