http://pics.ncrmnt.org/projects/mercury-mw150r/ TODO: Move them to the wiki.

This can be VERY rough for newbies. Web update is NOT tested and (likely) will not work if you have a VxWorks one. On the contarary, upgrade via web might work if you have a brick running proper linux.

Prereqs: soldering skills, smt rework station with hot air gun, some coffee This router can have up to 64MiB of RAM making it ideal for running some more services. However, this will require some soldering skills. First, identify how much RAM you have. If you are running on 8MiB RAM, you'll need one 22 Ohm resistor. 0402 is what they usually expect, 0603 also fits nicely. You can get a list of compatible RAM chips from this page: http://wiki.openwrt.org/toh/tp-link/tl-wr703n Once replaced, the router should boot. VxWorks bootloader will ALWAYS detect 8MiB of RAM.

The biggest flash upgrade possible (and tested my me) is 16 Megs. You'll need:

1. Soldering skills
2. Some AR9331 router with u-boot. WR703 fits in nicely.
3. A spare flash chip of 4 8 or 16 megs (16 megs will require a diy adapter due to a different footprint.
4. A linux box with dd, flashrom
5. A programmer supported by flashrom. I used buspirate
6. Optional flash adapters for easier connections

So, let's start.

1. Desolder the flash chip from the mercury and place it into the programmer. I used bus pirate+a diy converter board.
2. Use flashrom to dump the chip. e.g. flashrom -p buspirate_spi:dev=/dev/ttyUSB0 -r factory_2MiB_vxworks.bin. We'll need it to etract radio test data for wireless.
3. Extract the art section. This is 'atheros radio test', with wireless calibration data that is HARDWARE specifik. Failing to do so will bring you router to FCC regulators incompliance, or, what is worse - to shitty wireless performance. ART is usually the last 64KiB of the chip, so doing a dd if=./factory_2MiB_vxworks.bin of=art.bin skip=2031616 bs=1 will give you a good result.
4. Now, grab a chip from WR703N (stock firmware will do nicely as well) and dump it as well.
5. Place the spare chip into the programmer, and do the following.
   1. If you are good with 4MiB - just copy it and proceed to copying the ART section.
   2. Depending on the size of chip create a dummy empty file with dd: dd if=/dev/zero of=./target.bin count=16384 bs=1024 for the 16MiB flash use count=8192 for 8MiB flash chip.
   3. Copy the bootloader and firmware over it: dd if=./wr703ndump.bin of=./target.bin conv=notrunc
   4. Write the ART section over it: dd if=./art.bin of=./target.bin conv=notrunc seek=16711680 bs=1
   5. Burn the image to the chip: flashrom -p buspirate_spi:dev=/dev/ttyUSB0 -r target.bin
6. Solder the chip into the router and see if it boots. If it boots, and whatever firmware you put in there started the wireless - then you're lucky. You can not proceed to compiling and setting up OpenWRT as usual

You can grab the layouts of the flash adapters I used (as seen on the photos) at my github repo: https://github.com/nekromant/flashadapters