[FS#205] Cannot install LEDE on Ubiquiti PicoStation M2

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Bill Moffitt (bmoffitt) 

Attached to Project - LEDE Project
Summary - Cannot install LEDE on Ubiquiti PicoStation M2
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - High
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - This is the same as issue 20982 on dev.openwrt.org

Using the nightly build of LEDE and installing on a Ubiquiti PicoStation M2 (Ar7xxx, XM hardware rev, AirOS 5.6.3), got the following error:

sent DATA 
received ERROR 
Error code 2: Firmware check failed
Sent 3407872 bytes in 6.6 seconds

The only work-around I have found works consistently is to:

Flash from recovery (tftp) the AirOS 5.6 image,
Downgrade to AirOS 5.5, then
Flash LEDE (or OpenWRT).

This same error seems to occur on the Bullet M2 (same hardware) and the NanoStation LOCO M2.

The severity is high - it can be worked around, but it prevents installation without significant work-arounds. I view this as a high-priority bug, because the Ubiquiti hardware is popular and the problem has been fixed in AirOS and DD-WRT.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=205