after moving the affected IO board to slot 3 instead of slot 1, I get this:

0,0>Power is adequate, load 4 ps 2
0,0>    Check Board Present Test
0,0>    Board Present Interrupt Test
0,0>POST Failed
0,0>
0,0>    System Board Status
0,0>-----------------------------------------------------------------
0,0> Slot   Board Status     Board Type      Failures
0,0>-----------------------------------------------------------------
0,0>  0  | Normal         |+CPU/Memory  |
0,0>  1  | Normal         | CPU/Memory  |
0,0>  2  | Normal         |+CPU/Memory  |
0,0>  3  | Online/failure | IO Type 1   | FPROM
0,0>  4  | Not installed  |             |
0,0>  5  | Not installed  |             |
0,0>  6  | Not installed  |             |
0,0>  7  | Not installed  |             |
0,0> 16  | Normal         | Clock Board |
0,0>-----------------------------------------------------------------
0,0>
0,0>    CPU Module Status
0,0>-----------------------------------------------------------------
0,0> MID  OK  Cache  Speed   Version
0,0>-----------------------------------------------------------------
0,0>  0 | y | 8192  |  400  | 00170011.a0000507
0,0>  1 | y | 8192  |  400  | 00170011.a0000507
0,0>  2 | y | 8192  |  400  | 00170011.a0000507
0,0>  4 | y | 8192  |  400  | 00170011.a0000507
0,0>  5 | y | 8192  |  400  | 00170011.a0000507
0,0>-----------------------------------------------------------------
0,0>System Frequency (MHz),fcpu=400, fmod=200, fsys=80, fgen=400
0,0>    Populated Memory Bank Status
0,0>            bd #    Size    Address Way     Status
0,0>            0       2048    0       4       Normal
0,0>            0       2048    2       4       Normal
0,0>            2       2048    1       4       Normal
0,0>            2       2048    3       4       Normal
0,0>
0,0>
        POST COMPLETE

0,0>Entering OBP

ttya initialized
Using POST's System Configuration
Setting up memory
Starting CPU ID 1
Starting CPU ID 2
Starting CPU ID 4
Starting CPU ID 5
Clock board TOD does not match TOD on any IO board.
fhc ac simm-status environment sram flashprom SUNW,UltraSPARC-II SUNW,UltraSPARC
-II
fhc ac simm-status environment sram flashprom SUNW,UltraSPARC-II
fhc ac simm-status environment sram flashprom SUNW,UltraSPARC-II SUNW,UltraSPARC
-II
Probing UPA Slot at 6,0   sbus fhc ac environment flashprom eeprom sbus-speed co
unter-timer
Probing UPA Slot at 7,0   sbus counter-timer
Probing /sbus@6,0 at d,0  SUNW,soc
Probing /sbus@6,0 at 1,0  ba
Probing /sbus@6,0 at 2,0  Nothing there
Probing /sbus@7,0 at 3,0  SUNW,hme SUNW,fas sd st
Probing /sbus@7,0 at 0,0  QLGC,isp invalid command
sd st
8-slot Sun Enterprise 4000/5000, No Keyboard
OpenBoot 3.2.30, 8192 MB memory installed, Serial #8072394.
Copyright 2002 Sun Microsystems, Inc.  All rights reserved
Ethernet address 8:0:20:7b:2c:ca, Host ID: 807b2cca.



{0} ok