There are sources for set-top-box with STi71xx, they may help for hacking TV firmware.
Pls let me know if you can download from pudn.
You can use umicom.img to stop watchdog from U-Boot command line. This gives more comfort for U-Boot environment configuration. And enables serious repairs by flashing partitions from U-Boot. See more info http://wiki.samygo.tv/index.php5/Watchd ... s%28SH4%29