To run custom firmware on the Edimax BR6104K/KP, one first needs a way to transfer files to the Edimax router. Due to checks put in place by Edimax, custom firmware cannot be transferred via the web interface. The most common and reliable alternative method is a serial cable. On the board, there is a section of 8 pins called JP2, and pins one and two should be labeled; these can be used for 115200 8-N-1 serial communication. It's possible to create a serial cable from a Siemens mobile phone datacable; for instructions, check out the midge site. For this project a MAX3232 was used (TSSOP, produced by TI) to do the level conversion. A small pcb was put together (schem.pcb, diagram.bmp) and some .1" headers/sockets were soldered to the board. The final result looks like this and gets mounted like this. To see how the serial cable should be wired up, look at this image (ignore the pins on the left; that's for a different piece of hardware).
Once the serial cable/PCB have been made and attached to the router, it's possible to set up HyperTerminal in Windows, connect it to COM1, and watch the router boot. If the space key is pressed three times in rapid succession immediately after power is applied, a boot menu comes up. From this boot menu, new firmware can be loaded; however, the BR6104K/KP ships with a bootloader that looks for a very specific header in the kernel image it decompresses from flash, so be careful which firmware gets uploaded. For custom software development, it's recommended that a custom bootloader is used to provide more flexibility. The one used in this project is available here along with instructions on how to use it. Once that bootloader is installed, it's fairly straightforward to install the latest kamikaze version (the midge kernel) to the flash memory, but it will likely be running from SDRAM already if the instructions for using the TFTP client were properly followed.
At this point, the router will be running midge with a custom bootloader. For more information on what to do with the router from here on, the best place to look is the midge site, specifically the forums.
