jtagging foxy box

[gareth41]

Managed to get hold of foxy box with bluey that hasnt been powered on since the changes. Could anyone advise on how to dump the firmware? Where to get a jtag device from?

[vautek]

More information is need first, What is the model of your box.

[gareth41]

model DC420NF

[couchpotato]

If there is a jtag port on these ( I dont think there is from earlier inspection of one ) then you will need a jtag device for sgs ST20 type cpu. It may very well have a jtag but scattered to different test points around the board, you would need to remove the main chip to trace the points. There is a 10pin header on the board but the voltage levels dont match to be jtag, too many vss and vcc.

If you get as far as hooking up a jtag and have communication working then you will most probaly find its locked out to actually do anything but read the cpuid, eg no dumping.

The pace ds250 is jtag locked in this way, I can read the cpuid but cant halt it to dump the flash.

If I had one I didnt have to give back to foxtel I would use my smd rework station to remove the bga flash and use an bga to dip/tsop/plcc adapter to get its contents.

So unless you have specialised equipment your probably out of luck.