network issues / no network

Hi!

I dusted out my Ultra 2 for some tests. The nvram chip is empty... tried 
to fix it, but it shorted os I shorted it... well, a new one is in 
order, but for now I reset defaults and set a plausible mac address 
manually (original is lost forever? they are not printed with a sticker, 
aren't they?). I don't know if information is important, but I mention it.

At my first boot, the Ultra 2 showed 9.2 and I could do some basic 
network stuff, like downloading the 9.3 install kernel. Possibly it had 
ff:ff:ff:ff:ff MAC address, I don't know. From then I reboot into the 
9.3 upgrade kernel and have issues configuring network and can't 
download packages.. couple of attempts, I discover that back into 9.2 it 
doesn't work either.
Now I am somehow stuck.

I set the date manually to a good one, it always help.

dmesg:
[     1.000000] hme0 at sbus0 slot 14 offset 0x8c00000 vector 21 ipl 6: 
Sun Happy Meal Ethernet (SUNW,hme
)
[     1.000000] hme0: Ethernet address ef:82:20:c0:4d:f4
[     1.000000] nsphy0 at hme0 phy 1: DP83840 10/100 media interface, rev. 1
[     1.000000] nsphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto


ifconfig:

hme0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
capabilities=3c00<TCP4CSUM_Rx,TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx>
         enabled=0
         ec_capabilities=1<VLAN_MTU>
         ec_enabled=0
         address: ef:82:20:c0:4d:f4
         media: Ethernet autoselect (100baseTX full-duplex)
         status: active
         inet 192.168.1.15/24 broadcast 192.168.1.255 flags 0x0

this sounds plausible, isn't it?

The only thing I can think is that I poisoned the ARP table of some 
device, or that I invented a bad address?

Riccardo