[FS#830] No SSH Access to Device TP-Link MR3420 V2 (even in failsafe)

[LEDE Bugs]

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

User who did this - nouman8 (nouman8) 

Attached to Project - LEDE Project
Summary - No SSH Access to Device TP-Link MR3420 V2 (even in failsafe)
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 - Yesterday i reported bug #828 which was fixed few hours later so i build toolchain from git trunk sources successfully on my Archlinux machine. on make menuconfig i selected profile tp link mr3420 v2 and only changed gcc toolchain version to 7.x and images were build successfully. i flashed sysupgrade image and lost ssh access to the router i could ping 192.168.1.1 but when trying ssh root at 192.168.1.1 it shows "ssh: connect to host 192.168.1.1 port 22: Connection refused" and even in FAILSAFE mode it shows the same error..
so i opened the router for serial access and run top command process "dropbearkey -t rsa -f /tmp/d" was running non stop with 100% cpu utilization...after that i reboot into the bootloader and flashed daily snapshot for mr3420v2 which restored ssh access.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=830