Excerpt from the Sun NVRAM/HostID FAQ


SparcClassic /Classic X Terminal NVRAM differences

This section was supplied by Gary Cook. I have not been
able to try this personally because I don't currently have access to this
type of machine.

Change the following locations in NVRAM to switch between Classic and
Classic

 Address   ClassicX Value  Classic Value

 71202004  ff              00

 71202005  12              00

 71202006  08              00

 71202007  36              00

Notes:

   * Classic X requires all locations to be set to above values. If they are
     not, the system takes on the Classic personality.
   * Bootprom for Classic X cannot be Version 2.9. This version will ignore
     the above NVRAM changes. Classic X requires earlier versions, such as
     2.12.

Procedure

Classic --> Classic X

ok
ff 71202004 20 spacec!
12 71202005 20 spacec!
08 71202006 20 spacec!
36 71202007 20 spacec!

Classic X --> Classic

ok
00 71202004 20 spacec!
00 71202005 20 spacec!
00 71202006 20 spacec!
00 71202007 20 spacec!