When users refer to "Pixhawk 248," they are almost always talking about the Pixhawk 1 autopilot hardware, specifically the version 2.4.8 board. This was the most widely produced and cloned version of the original Pixhawk design.
Navigate to the official ArduPilot firmware archive (firmware.ardupilot.org). Path:
/ArduCopter/stable-3.2.4/ pixhawk 248 firmware
Look for: ArduCopter-v3.2.4-px4-v2.px4 (Note: The ".px4" extension is the binary file for Pixhawk, despite being ArduCopter). When users refer to "Pixhawk 248," they are
Do not use the "hex" file unless you are using a bootloader recovery tool. ArduPilot had started on Arduino-based APM 1
Around ArduCopter 3.6, the code size exceeded the 2MB flash limit of the original Pixhawk. Developers had to strip features. Version 248 requires zero stripping. It runs the full feature set of its era without skimping on safety checks.