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AP51-FLASH(8) System Manager's Manual AP51-FLASH(8)


ap51-flash - firmware flasher for ethernet connected routers and access points


ap51-flash [ -vh ] [ -m mac ] [ interface image ... ]


ap51-flash listens on traffic of a network interface, detects remote devices and checks the traffic for known identification markers. These markers are send out automatically by supported devices during the initial boot process of the embedded boot loader.

On success, it will search the list of provided images for a matching firmware. A device specific communication procedure is initiated to begin the flashing process. The firmware data is extracted from the selected image and transferred to the device in TFTP server or client mode.

ap51-flash will run in foreground and continue using the interface until it is interrupted by an SIGINT signal (typically generated by control-C) or SIGTERM signal (for example generated by the kill(1) command).

The interface doesn't require a valid layer 3 network configuration but has to be set in the UP state (using the ip-link(8) command). ap51-flash requires enough privileges to capture and inject raw ethernet packets on the selected interface. These are often only accessible to the root user.

While ap51-flash doesn't require a target device specific network configuration or TFTP client/server on the same machine, it is recommended to disable any other TFTP client or server on the system running ap51-flash to avoid interferences by a different TFTP program.


Listed below are the command line options for ap51-flash:

Adds mac address to the allowlist filter. Only these addresses will be tried to be flashed when one or more addresses are supplied. The option has to be supplied multiple times to add multiple addresses to the allowlist filter. If not specified, all detected devices will be flashed.

print ap51-flash version and exit

print ap51-flash help and exit


The currently supported devices are

  • Alfa Network AP121F
  • Datto AP440
  • Datto AP840
  • Datto AP840E
  • Datto TW420
  • Dlink DIR-300
  • Engenius EOC-1650
  • Engenius EOC-2610
  • Engenius EOC-2610p
  • Engenius 3660
  • FON La Fonera (2100)
  • Open Mesh A40
  • Open Mesh A42
  • Open Mesh A60
  • Open Mesh A62
  • Open Mesh D200
  • Open Mesh G200
  • Open Mesh MR500
  • Open Mesh MR600 (v1, v2)
  • Open Mesh MR900 (v1, v2)
  • Open Mesh MR1750 (v1, v2)
  • Open Mesh OM1P
  • Open Mesh OM2P (v1, v2, v4)
  • Open Mesh OM2P-HS (v1, v2, v3, v4)
  • Open Mesh OM2P-LC
  • Open Mesh OM5P
  • Open Mesh OM5P-AN
  • Open Mesh OM5P-AC (v1, v2)
  • Plasma Cloud PA300
  • Plasma Cloud PA1200
  • Plasma Cloud PA2200
  • Plasma Cloud PAX1800 (v1, v2)
  • Ubiquiti Bullet2 & HP
  • Ubiquiti NanoStation2
  • Ubiquiti NanoStation5
  • Ubiquiti Pico2 & HP
  • Ubiquiti RouterStation
  • UniAppliance Colibrì (!UniData)
  • Zyxel NBG6817


ap51-flash was written by Marek Lindner and others. This manual page was written by Sven Eckelmann <>. It is licensed under the terms of the GNU GPL (version 3 or later).

August 29, 2019