Default [Q] T-Mobile S2 T989 - hardbricked / can jtag fix it?

I received an SGH-T989 that wouldn't boot. It had TWRP on it, so I was able to flash latest stable CWM. Upon reboot, it apparently became hard-bricked.

Currently, I'm unable to enter download or recovery modes. USB Jig does not work. There is no output on the screen, even when charging the battery. When connected in Windows (32 or 64), I get a usb error message: "This device is disabled because the firmware of the device did not give it the required resources. (Code 29)"

My question: Is the motherboard dead, or could a jtag repair fix it?

What I've tried:
  • multiple micro usb cables
  • usb jig
  • odin
  • keis
  • heimdall

Thanks xda!