SUN Fire v20z BIOS update problem

Hi all.

After 6 successful SP and BIOS update on other v20z, I've tried to
update an SUN Fire v20z BIOS (after the SP update) and now it doesn't
boot.

I followed this thread:
http://fixunix.com/sun/113979-proble...t-anymore.html

I did follow all the steps, but it seems that my BIOS was completely
erased.

This is the output of the command "inventory get all":
************************************************** *************************************************
Name Revision Install Date Description
SP Value-Add V2.4.0.20 Mon Apr 27 17:22:17 2009 SP Value-Add Software
SP Base V2.4.0.20 Mon Apr 27 17:22:17 2009 SP Base Software

Name Type OEM Manufacture Date
Hardware Revision Part #
CPU 0 DIMM 0 memory ce00000000000000 2004-05-20
5345 M3 12L6420ETS-CA2
CPU 0 DIMM 1 memory ce00000000000000 2004-05-13
5345 M3 12L6420ETS-CA2
CPU 0 DIMM 2 memory ce00000000000000 2004-12-09
5345 M3 12L6420ETS-CA2
CPU 0 DIMM 3 memory ce00000000000000 2005-05-21
5345 M3 12L6420ETS-CA2
DDR 0 VRM memvrm S-SCI448 2005-12-08
A01 S01479
CPU 0 VRM vrm S-SCI448 2005-12-17
A01 S02325
CPU 1 DIMM 0 memory ce00000000000000 2005-02-19
5345 M3 12L6420ETS-CA2
CPU 1 DIMM 1 memory 2cffffffffffffff 2003-08-20
0000 18VDDT6472G-26AC0
DDR 1 VRM memvrm S-SCI448 2005-12-20
A01 S01479
CPU 1 VRM vrm S-SCI448 2005-12-17
A01 S02325
PIC frontpanel NA
Motherboard planar S-SCI448 2005-12-21
A05 S03904
PRS Software os 2009-04-27 97.0
Power supply power ACBEL 2005-06-24
A-01 S01899
SCSI backplane scsi_backplane S-SCI448 2005-12-10
A02 S01194
************************************************** *************************************************

When I try to update the BIOS, this is what I get every time:
************************************************** *************************************************
localhost $ platform set os state update-bios /mnt/nsv-v20z-
bios_1.35.5.1/sw_images/platform/firmware/bios/V1.35.5.1/bios.sp
This command may take several minutes. Please be patient.
Bios started
Error. The operation timed out.
localhost $
************************************************** *************************************************

The SP is OK. I can connect via SSH and all. I just can't force a BIOS
update.
I've tried pretty much everything, including copying the bios.sp to
the SP's /tmp, factory resets, clear CMOS, ...
When I power on the server with a monitor, no image is shown on the
screen, not even an error code.

I wonder if anyone could give some hints on how to solve this.

Thanks in advance,
Luis Monge.