One brand of electronic countermeasure would cause a firmware write that wouldn’t allow the receiver to boot because you’re a lazy hacker that didn’t lock the flash chip at the hardware WE pin level.
There were a couple of strategies to resolve:
1) remove chip and re-program (not fun on TSOPs)
2) JTAG reprogram (easy and cheap when computers had parallel ports: just some wires and a DB25 connector and the port can bit bang everything)
3) the device does a Power on self test. If it detects a corrupted flash file, it will grab a fresh and clean one from the satellite stream and overwrite your nasty one. You can trigger this by shorting/grounding the right address lines on the flash chip at the right time in the self-test. It won’t pass checksum validation and will think a corrupted update occurred and rewrite it.
That was all for the parallel flash chip (a 28 or 29f series I think).
If it was a serial flash chip like a 24 series, that would be even easier to deal with.