[FS#889] Installing LEDE v.17.01.2 will brick Edimax BR-6475ND

[LEDE Bugs]

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

User who did this - docplastic (docplastic) 

Attached to Project - LEDE Project
Summary - Installing LEDE v.17.01.2 will brick Edimax BR-6475ND
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Critical
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details -  - tree/revision: v.17.01.2, ramips, rt3883;

 - affected device: Edimax BR-6475ND;

 - What does it do: It gets stuck into an infinite boot loop;

 - Steps to reproduce:
  a) on a properly working LEDE v.17.01.0, do a standard upgrade to v.17.01.1 (both not keeping or keeping settings will get the same result);
  a) on a properly working openwrt V.15.05.1, do a standard upgrade to v.17.01.2 (both not keeping or keeping settings will get the same result);

 - What I have already done to fix the problem: To recover, one must put router into failsafe mode and sysupgrade to openwrt V.15.05.1 (file https://downloads.openwrt.org/chaos_calmer/15.05.1/ramips/rt3883/openwrt-15.05.1-ramips-rt3883-br-6475nd-squashfs.bin).
 - What does work: upgrade from openwrt 15.05.1 to LEDE 17.01.0 , we get a properly working router.
 - What does not work: upgrade from openwrt 15.05.1 or LEDE 17.01.0 to LEDE 17.01.2 or LEDE 17.01.1

 - What else does not work: erasing these report bugs without addressing the reported bug.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=889