[FS#380] sysupgrade corrupts firmware on ASUS RT-N16

[LEDE Bugs]

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

User who did this - Nikolay Amiantov (abbradar) 

Attached to Project - LEDE Project
Summary - sysupgrade corrupts firmware on ASUS RT-N16
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - On ASUS RT-N16 doing a sysupgrade results in a bootloader presumably detecting corrupted firmware and entering ASUS rescue mode. After the same image (which has been supplied to sysupgrade before) is pushed via TFTP router boots successfully. FWIW JFFS2 contents (that is, settings) are not lost.

Revision: 3e7b894ac08b56343e6e449a38fdb2be7b02a127

Steps to reproduce:
1. Run `sysupgrade lede-brcm47xx-mips74k-asus-rt-n16-squashfs.trx`;
2. Wait until router reboots;
3. Observe ASUS bootloader falling back to the rescue mode.

OpenWrt bug: https://github.com/openwrt/openwrt/issues/318

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=380