Help with failed CS20

[Stephen Lewis]

To all fellow Alpha caretakers,

I had a CS20 power supply quit - went to solid red LED and would not start,
I obtained a replacement power supply and now it powers up to solid green LED
but now I have a new problem which I have never seen before:

Instead of booting I get this message very early after powerup:

Bad Memory or ROM?
J14 J16 J18 J20(Bank 0)
 ff  ff  ff  ff
J15 J17 J19 J21(Bank 1)
 ff  ff  ff  ff.3f.06

at this point it seems to hang indefinitely but if I hit <CR> I get:

SLRP V02050202
Break (ff) from 00004740
SROM> 

where it stays until I hit a key <CR> gets the prompt all other keys get:

Error:

I "rotated" the memory chips 1->2 2->3 3->4 and 4->1 so that none are
in orignal location. I get the exact same response so I conclude that
it is the ROM not the memory - I get this output before (ie instead of)
the "Testing Memory" message that I used to get. If I was to guess I'd
say that somehow the SRM in boot PROM got blown away (can the PS do that?)
and it looks like maybe the "SROM>" prompt is waiting for data to re-flash
the PROM - maybe from the serial console but I don't know how to do that
nor do I have a ROM image file.

Can anyone confirm above diagnosis and point me in the direction of
re-flashing SRM - bear in mind that the CS20 does not have a floppy drive,

Thanks,
Stephen Lewis