last thing i've done on the wrt54g:
root@ixolite:~# md5sum openwrt-brcm47xx-2.6-squashfs.trx 
f1fd6e7f7eeeaffb4204c2f14911b5af  openwrt-brcm47xx-2.6-squashfs.trx
root@ixolite:~# mtd -r write openwrt-brcm47xx-2.6-squashfs.trx linux
Unlocking linux ...
Writing from openwrt-brcm47xx-2.6-squashfs.trx to linux ...  [w]

output from the serial:
root@ixolite:/# Restarting system.                                              
Please stand by while rebooting the system...                                   
                                                                                
                                                                                
CFE version 1.0.37 for BCM947XX (32bit,SP,LE)                                   
Build Date: Fri Feb 27 15:23:38 CST 2004 (root@honor)                           
Copyright (C) 2000,2001,2002,2003 Broadcom Corporation.                         
                                                                                
Initializing Arena.                                                             
Initializing Devices.                                                           
et0: Broadcom BCM47xx 10/100 Mbps Ethernet Controller 3.50.21.0                 
CPU type 0x29007: 200MHz                                                        
Total memory: 0x2000000 bytes (32MB)                                            
                                                                                
Total memory used by CFE:  0x80334DC0 - 0x8043A310 (1070416)                    
Initialized Data:          0x80334DC0 - 0x80336F40 (8576)                       
BSS Area:                  0x80336F40 - 0x80338310 (5072)                       
Local Heap:                0x80338310 - 0x80438310 (1048576)                    
Stack Area:                0x80438310 - 0x8043A310 (8192)                       
Text (code) segment:       0x80300000 - 0x8030F220 (61984)                      
Boot area (physical):      0x0043B000 - 0x0047B000                              
Relocation Factor:         I:00000000 - D:00000000                              
                                                                                
Boot version: v2.3                                                              
The boot is CFE                                                                                                        
mac_init(): Find mac [00:0F:66:A7:2E:A7] in location 1                          
Nothing...                                                                      
Device eth0:  hwaddr 00-0F-66-A7-2E-A7, ipaddr 192.168.1.1, mask 255.255.255.0  
        gateway not set, nameserver not set                                     
Reading :: Failed.: Timeout occured                                             
Loader:raw Filesys:raw Dev:flash0.os File: Options:(null)                       
Loading: .. 3732 bytes read                                                     
Entry at 0x80001000                                                             
Closing network.                                                                
Starting program at 0x80001000