In the Hardware options page in the Wiki, there is a statement about Linux Based Autopilots saying that “Linux boards usually have more CPU power and memory many of the other boards listed on this page, but do not support DShot, Bi-Directional DShot, BLHeli ESC passthrough, many of the ArduPilot GPIO based features, and easy upload from the ground stations.”, which GPIO pins are not supported?
Thanks for your time.
In true, each Linux board has features that can not be available in others.
For instance, PWM generation in beaglebones are made in the PRU of beagles, meanwhile on raspberry py usually PCA9658 is used.
GPIO pins can be shared between resources - a gpio pin can be used as spi bus or maybe an I2C bus instead a gpio general pin, so when the ardupilot is customized by some board, there are decisions - what is more important for a pin, gpio or bus and this is the main reason the gpio is board dependent.
best regards.