Here's a good starting point:http://magiclantern.wikia.com/wiki/Developing_info
- setup arm toolchain to have arm gcc and compiler tools
- download source code from official repository: www.bitbucket.org/hudson/magic-lantern
- start porting, follow the 5dc and 40d ports since they are both vxworks as well.
first step is to extract a firmware update from a signed canon updater (refer to tools here
_. after you have mapped some of the firmware out and understand how it works, begin porting ML.
Adapt cache_hack boot method from 40D init.c (under platforms/40d folder in ML sourcecode) and boot the main firmware, while hooking your first task in.
Then, enable bootflag (to allow booting with autoexec.bin file), then dump the whole firmware (0xFF810000 - 0xFFFFFFFF). enabling the bootflag will allow you to boot with just the autoexec.bin file without packing it into a signed FIR update file.
More info on packing FIR files for older cameras: http://magiclantern.wikia.com/wiki/Packing_FIR_Files
You can find the tools you need there too (links to them).