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Bootloader-level JTAG flag in config.txt? #639
TL; DR: By adding
This may be a weird idea, but I think it can be useful for newbies in bare metal programming. This allows JTAG being used before a working bare metal kernel is written into the SD card, enabling debugging the earliest parts of the kernel.
The missing-kernel JTAG allows developing kernels without having to switch in and out SD cards (wearing down the card and the connector) or a working bootloader (so serial loading can work - in fact for Pi 3 serial loading may never work due to the UART timer scaling issue.) Kernels can be injected directly into the RAM and booted in-place using JTAG.
Additionally a new flag