I've been having a lot of trouble getting my (old) Ultra 5 to boot.

I've connected a terminal emulator to serial port a on my Sun and run
the Power On Self Test (POST) several times and it never fails, even
with dial-level max.

The trouble seems to happen after the reset or power-on

Clearing I/D TLBs Done
Probing Memory Done
MEM BASE = 0000.0000.1000.0000
MEM SIZE = 0000.0000.1000.0000
11-Column Mode Enabled
MMUs ON
Copy Done
PC = 0000.01ff.f000.201c
PC = 0000.0000.0000.2060
Decompressing into Memory Done
Size = 0000.0000.0006.e770
ttya initialized
Reset Control: BXIR:0 BPOR:0 SXIR:0 SPOR:1 POR:0
UltraSPARC-IIi 2-2 module
Probing Memory Bank #0 0 + 0 : 0 Megabytes
Probing Memory Bank #2 128 + 128 : 256 Megabytes
Probing UPA Slot at 1e,0 Nothing There
Probing /pci@1f,0/pci@1,1 at Device 1 pci108e,1000 network
Probing /pci@1f,0/pci@1,1 at Device 2 SUNW,m64B
Probing /pci@1f,0/pci@1,1 at Device 3 ide disk cdrom
Probing /pci@1f,0/pci@1 at Device 1 Nothing there
Probing /pci@1f,0/pci@1 at Device 2 pci
Probing /pci@1f,0/pci@1/pci@2 at Device 0 Data Access Error

whenever I do a reset I get
Data Access Error

If I try to boot I get
ok boot disk
Boot device: /pci@1f,0/pci@1,1/ide@3/disk@0,0 File and args:
Memory Address not Aligned
ok boot disk
Fast Data Access MMU Miss

At this point whenever I try to boot from disk I get Fast Data Access
MMU Miss, until I reset and start all over again.

Does this indicate a problem with the disk? The disk isn't that old, and
when my Ultra 5 does boot the OS seems to run fine.

Any help or advice would be appreciated.

-- Eric