SD Over USB - portapack-mayhem/mayhem-firmware GitHub Wiki

SCR_0011 SCR_0013

Screenshot 2023-04-01 193341

The SD Over USB app exposes the SD card as a USB Mass Storage device, allowing a connected PC to read and write files directly — without physically removing the card.

This is an External-apps-informations (.ppma file on the SD card).

[!NOTE] When SD Over USB is active, normal PortaPack operation is completely suspended. The device runs a dedicated USB Mass Storage firmware — no other apps or functions are available until the PortaPack is restarted.

Usage

  1. Connect the PortaPack to a PC via USB.
  2. Open SD Over USB from the Utilities menu.
  3. Press the Run button.
  4. The screen clears and the HackRF icon appears on a black background — this indicates USB Mass Storage mode is active.
  5. It can take up to 20 seconds for the drive to appear on the PC.
  6. Use the SD card as you would any external drive — copy, delete, or modify files freely.

Exiting USB Mass Storage mode

There is no exit button. To return to normal PortaPack operation, first safely eject / unmount the drive on your PC, then power cycle the device. On the H4M use the power switch; on older models (H1, H2) double-press the encoder knob to turn off, then press once to turn on.

[!WARNING] Always unmount the drive on your PC before power cycling — failing to do so may cause filesystem corruption on the SD card.

Performance

Transfer speed is approximately 400–500 KB/s. This is a hardware limitation of the USB connection. For large file transfers, physically removing the SD card and using a card reader may be significantly faster.

For example, copying the 2 GB world_map.bin file to the SD card via SD Over USB can take up to 2 hours. Using a card reader directly is much faster.