An Open JTAG Debugger

Presented at DEF CON 17 (2009), Aug. 1, 2009, 4:30 p.m. (50 minutes)

While it's simple enough to build a "Wiggler" JTAG adapter for the PC parallel port, there is very little open hardware for performing high-speed programming of JTAG devices by USB. This lecture introduces the GoodFET, an open source USB JTAG adapter which can be reflashed to support the programming and debugging of any number of chips. Both hardware and firmware are compared to that of a similar, commercial design. This lecture will also cover the details of the JTAG standard and a few of its competitors, as well as the possibility of attacking these debugging modes when access has been denied or restricted.


  • Travis Goodspeed - Engineer of Superior Buckles, Goodspeed & Gourneau
    Travis Goodspeed is a neighborly reverse engineer from Southern Appalachia. He has been exploiting and reverse engineering wireless sensors since writing the first stack overflow exploit for them in 2007. His recent projects have included a timing attack on the MSP430 bootstrap loader and an extra-neighborly party-mode belt buckle in the shape of Tennessee.