booting to install - GRUB

Hi,

I attempt to install Debian on my Ultra1
My idea would be to start with the Debian 12 netinst ISO which hopefully 
has a working kernel and then proceeed with testing of Adrian's kernel 
and also carefully update packages.

As the cases of these old systems are becoming brittle, the NVRAMs 
become "forgetful" so may be optical media.

I tried booting with the CDROM of the U1, nothing happens, I think it is 
busted (or dirty or who knows...)
I tried using the CDROM drive of the U2 in the U1 and also in the U2 
(just for tests) and it gets as far as printing GRUB and then hangs.

I don't know if the old optical drives all wonky or if there is an issue 
booting on these older systems or both.

Fine... alternative solutions. Trusted Netra T1 is currenlty off-duty 
because it needs two module RAM replacement, but 1GB is still plenty for 
an install, cdrom works and Disk Sleds is an easy swap.
So I start booting and here indeed GRUB comes up, language selection, 
etc etc... but then:
   lqqqqqqqqqqqqqqqqqqqqu Loading additional components 
tqqqqqqqqqqqqqqqqqqqqk
x x
   x 37%                                   x
x x
   x [  340.718293] watchdog: BUG: soft lockup - CPU#0 stuck for 26s! 
[tar:2157]
[  364.718292] watchdog: BUG: soft lockup - CPU#0 stuck for 48s! 
[tar:2157] x
[ 1444.718281] watchdog: BUG: soft lockup - CPU#0 stuck for 1054s! 
[tar:2157]

I waited long, but the CD drive LED goes off. I tried two different 
media, even a real CD-R and not CD-RW. Both stuck ad 37%

Can't be a coincidence? even a flakey disc drive would fail in a 
different place on two different media.

Disturbed, I tried the Fire v120 ... different drive, that finally 
completes. Wow. Bad luck or strange issues?

Here I went all with the most default setup, I got this warning:

     x The disk has 69369 cylinders, which is greater than the maximum 
of  x
     x 65536. x

Maybe some screwed calculation? I just continued... and the system 
booted debian 12 on the Sun Fire 120

Now the long process of setting it up from the minimal CD started: no 
sshd, no proper keys, no gpg, wrong sources... exhausting.

Still, I have a booting system with kernel on the sun Fire V120 - the 
"host installer"
Linux debian-sparc64 6.1.0-9-sparc64 #1 Debian 6.1.27-1 (2023-05-08) 
sparc64 GNU/Linux

Now I set my sources to unstable and run upgrade. Reboot ... and am in.
Now time for "dist-upgrade" and see what happens.

Loading Linux 6.16.7+deb14-sparc64 ...
Loading initial ramdisk ...

Specifically:  6.16.7+deb14-sparc64 #1 Debian 6.16.7-1 (2025-09-11) sparc64

boots to prompt on serial and responds to ssh, so basic is there and no 
crash
cpu             : TI UltraSparc IIe (Hummingbird)
fpu             : UltraSparc IIe integrated FPU


Now tomorrow I should be able to test this on Ultra1 and perhaps with 
some luck on Ultra2 and see what happens and also test Adrian's kernels.

Riccardo