Connect to LAN1 and set your PCs IP address to 192.168.0.2
Hold down the reset button and power cycle the device
Keep holding the button until the Power/Status LED flashes yellow
Browse to http://192.168.0.1 user: admin, password:blank
Go to TOOLS | FIRMWARE http://192.168.0.1/tools_firmw.asp
Choose and Upload the firmware - either factory firmware, or another suitable uboot image such as DD-WRT, or soon, OpenWrt (trunk)
When this is working you will get a “Device is upgrading the firmware” page which cycles through from 0 to 100%
I had some troubles getting to this point: Firefox 15.0.1 on Linux amd64, hung at the 'Upload' screen. Chrome 21 on Linux amd64 actually uploaded, (as verified by wireshark) and then hung. I could only succesfully complete this procedure using Windows XP with IE8 (!) My experience contradicts what is documented on the DD-WRT website, which states that Firefox only works.
Flashing firmware with u-boot
This should be possible using TFTP, as desribed elsewhere: generic.flashing.tftp
However, I could not get it to work at all, the device would not properly respond to ARP and may have other issues - see post on the forum.
It is possible to load and run an INITRD kernel over the serial port using kermit, so with a bit more work this procedure can probably be extended to writing an image into the flash.
(Note: using Debian Linux, use `apt-get install ckermit` and run `kermit` )
Connect a TTL serial device (e.g. 3v3 TTL-USB adaptor, etc) to the pins shown in the above images
Power cycle the router
Using kermit, press enter to get to the u-boot menu when prompted. If needed configure to connect using 115200-8n1
At the prompt, type the following, this will wait for a file to be loaded to memory address 0x81000000 (16Mb through the RAM)
At this point, hit CTRL+/ (Control and Forward Slash) then hit C this will cause kermit to drop to a prompt
At the kermit prompt, type the following, where send «some-image-file» is the filename of the u-boot image. This works best if you run kermit from the same directory as the image.
This will cause kermit to upload the file. This will take several minutes.
When kermit returns to the prompt, hit C
At the uboot prompt, type
This will run the uimage from the default load address of 0x81000000
In case you get a brick in your DIR-632 yo can use procedure is similar to the DIR-620 and other related devices.