for web flashing use the whrag108-firmware.bin to upgrade a already installed dd-wrt using the webinterface. 




1.
mount a serial adapter to the device (max323 converter needed)
there are 2 sockets on the board. the second smaller one is the serial console we need (JP1)
pin 1 = rx
pin 2 = tx
pin 3 = GND
pin 4 = GCC +3V



2.
set your terminal client to 9600-8-N-1 

3.
enter the RedBoot console by pressing CTRL+C

4.
copy root.fs and lzma_vmlinus to your tftp server directory

5.
configure the RedBoot bootloader IP and TFTP server settings using
ip_address -l [local ip address] -h [remote server address]

6.
flash the unit by entering the following commands

RedBoot> fis init
About to initialize [format] FLASH image system - continue (y/n)? y
*** Initialize FLASH Image System
    Warning: device contents not erased, some blocks may not be usable

RedBoot> load -r -v -b 0x80041000 root.fs
Raw file loaded 0x80041000-0x802c1fff, assumed entry at 0x80041000

RedBoot> fis create -b 0x80041000 -f 0xbe050000 -l 0x002a0000 -e 0x00000000 rootfs
RedBoot> load -r -v -b 0x80100000 lzma_vmlinus

Raw file loaded 0x80100000-0x801af797, assumed entry at 0x80100000

RedBoot> fis create -r 0x80100000 -e 0x80100000 -l 0x000c0000 -f 0xbe2f0000 linux

RedBoot> fis create -f 0xbe3b0000 -b 0x80041000 -l 0x00010000 -e 0x00000000 nvram


if everything went well it should look like this:

RedBoot> fis list
Name              FLASH addr  Mem addr    Length      Entry point
RedBoot           0xBE000000  0xBE000000  0x00050000  0x00000000
RedBoot config    0xBE3DF000  0xBE3DF000  0x00001000  0x00000000
FIS directory     0xBE3D0000  0xBE3D0000  0x0000F000  0x00000000
rootfs            0xBE050000  0xBE050000  0x002A0000  0x00000000
linux             0xBE2F0000  0x80100000  0x000C0000  0x80100000
nvram             0xBE3B0000  0xBE3B0000  0x00010000  0x00000000

7.
configuring the bootloader

RedBoot> fconfig
Run script at boot: true
Boot script:
Enter script, terminate with empty line
>> fis load linux
>> exec
>>
Boot script timeout (1000ms resolution): 3
Use BOOTP for network configuration: false
Gateway IP address: 10.50.2.1
Local IP address: 10.50.2.109
Local IP address mask: 255.255.255.0
Default server IP address: 10.50.2.107
Console baud rate: 115200
DNS server IP address:
GDB connection port: 9000
Force console for special debug messages: false
Network debug at boot time: false
Update RedBoot non-volatile configuration - continue (y/n)? y


note that the ip addresses can be configured by you. these are only examples from my configuration

8.
rebooting

RedBoot> reset


consider to configure your terminal to 115200-8-N-1 now. otherwise you will not see any bootmessages