[rescue] SUN Ultra2 + 501-2480?

[Gutschner, Marc]

Hi!
 
I've recently "ePayed" a couple of 64MB DIMMs to give my Ultra2 a little more Oomph. But it appears that my machine doesn't like these modules :-( As far as I can tell from the barcode sticker the modules are "genuine SUN parts".
 
If I plug them in and switch the machine on, it displays the expected amount of total RAM (768MB) in the banner at the top of the display and says "Initializing memory". It "twiddles" around for a couple of seconds and then seems to stall, i.e. the message disappears and the cursors sits solid where the 'ok' prompt should appear.
 
Currently I've installed 256MB across 8 32MB modules. With this configuration the machine runs rock solid, albeit a little "huffing and puffing". So I've added the "new" modules in the remaining 2 banks - but "no go" :-( Replacing those 8 modules with 4 of the larger ones also exhibits above symptoms. Thus I think I can rule out a broken DIMM socket. May a firmware update be needed? At the moment it has OBP 3.19 and the latest one is 3.25...
 
I've consulted the systems handbook before buying the memory and it says that this module type should be supported. And in the release notes for the 3.25 firmware I've not found anything wrt/ to support for 64MB DIMMs...
 
MTIA for any hints and clues,
Marc