@Per_Magnus_Tveten – Good question. After digging into Framework’s QMK source code, it turns out the two-key combo is actually closer to hardware-level than MJ1 initially suggested, though it’s a bit nuanced.
Looking at Framework’s framework.c, there’s this comment:
// Before this, when holding down both alt keys QSPI_SS is pulled low
// to put the RP2040 in bootloader mode during reset.
The keyboard PCB has a hardware circuit that detects when both Alt keys (or keys 2+6 on macropad) are held during power-up and physically pulls the QSPI_SS (flash chip-select) line low. This happens before any firmware runs – it’s an electrical circuit on the PCB itself. The firmware’s only involvement is signaling “boot is complete” afterward via a GPIO pin (BOOT_DONE), which tells the hardware circuit to release the CS line.
So @MJ1 is correct that it’s not a traditional hardware button (like a Pi Pico’s BOOTSEL), but Framework designed it so the key detection happens at the hardware/electrical level, not in QMK firmware. That’s also why "bootmagic": false is set in Framework’s QMK config – they don’t use QMK’s firmware-level bootmagic at all.
Bottom line: even with totally corrupted firmware, holding those keys while reconnecting the module should still get you into bootloader mode. It’s a clever design on Framework’s part.