http://www.wheelsjamaicahost.com/wheels_forum/index.php?topic=78078.0 Thanks for posting my link. The person who started this topic should read it. I hate to repeat myself because thats why the post over there was created but here goes...
It is impossible to modify the stock programming on a Toyota ECU:
1) Because the Toyota doesn't use the traditional Multiple fuel tables. According to the operational manuals the Toyota has 1 table and then uses a formula to populate the cells of the other tables. Therefore even if you could read the ECU you'd only get one table and have to figure out the rest.
2)Toyota owns the chip maker and there is no commercially available 'disassembler' for it.
3)The aftermarket ECUs take the stock ECU out of the loop completely, according to Techtoms, and run their own motherboard. Most of these chips have some sort of protection. Many are hard glued to the board with resin, but some are light sensitive, others will rip themselves off the main board if you lift the case, some have a secondary chip on the back that decodes the data from the main chip, and others remove the name of the chip so you cant buy a reader. The problem is you dont know what method of protection each ECU uses. As stated in the article the JAM ECU for the 4AGE we tested erased itself upon exposure to sun as the owner removed the sticker over the photocell.