OpenOCD 0.11.0 and up works with CMSIS-DAP debuggers like the Raspberry Pi Debug Probe/Pico Probe and the Flipper Zero.
The Flipper Zero has an installable DAP Link app (through the companion mobile app) that supports SWD. The pinouts are straightforward: the DAP Link app tells you which GPIO pins are SWDCLK and SWDIO, respectively, and of course GND is GND.
Tested all five steps with OpenOCD 0.12.0 on macOS and Flipper Zero firmware 0.88.0. An example step looks like: `./2_backup_flash.sh cmsis-dap mario`. The G&W plays fine after all steps. Also tested with a Picoprobe.
(Also fixed two typos in the main README that are unrelated to this PR but very small.)
James Ide
Benjamin Sølberg
Konrad Beckmann
al3x10m
Thomas Roth