I just installed an HP Proliant DL 380 G3 with RHEL4. This worked fine until   
applied all latest patches from RHN. After that, the system cannot get   
the Ethernet address for the NIC and the rest of the init of the NIC   
fails subsequently. The tg3 driver is used. 
This problem happens once out of two reboots.   
   
Boot once, it works   
Reboot, it doesn't work   
Reboot, it works   
Reboot, it doesn't work   
[...]   
   
In dmesg, I can find the following for the problem boot:    
===    
tg3: Could not obtain valid ethernet address, aborting.    
tg3: probe of 0000:02:01.0 failed with error -22    
===    
And this for the OK boot:    
===    
eth0: Tigon3 [partno(TBD) rev 1002 PHY(5703)] (PCIX:100MHz:64-bit)    
10/100/1000BaseT Ethernet 00:0b:cd:f4:1a:67   
===   
   
I reverted back to kernel 2.6.9-34.ELsmp which seems to solve the problem for  
the time being.