I've been talking to someone using ev3dev with BrickPi. Apparently they [upgraded the firmware of an older BrickPi to v2.5](https://github.com/ev3dev/ev3dev/issues/796). From what I understand, firmware v2.5 is for BrickPi+ only and firmware v1.7.4 and v2.0 are for (older) BrickPi only. However, this is not documented in <https://github.com/DexterInd/BrickPi/tree/master/Firmware_BrickPi> or <https://www.dexterindustries.com/BrickPi/about/design/brickpi-firmware-update/>.