WRT1900ACS shows unauthorized on installation

[rcorre]

I just got a WRT1900ACS. I went through the initial Linksys setup, and am trying to install OpenWRT. Following https://openwrt.org/toh/linksys/linksys_wrt1900acs, I downloaded http://downloads.openwrt.org/releases/18.06.4/targets/mvebu/cortexa9/openwrt-18.06.4-mvebu-cortexa9-linksys-wrt1900acs-squashfs-factory.img, verified the checksum, and tried to install it via the Linksys GUI. When I go to Connectivity > Router Firmware Update > Manual, choose the image, and click start, I see

Unexpected Error
The firmware update did not complete successfully. Please try again later.
We've encountered an unexpected error. If the issue continues, please visit our Technical Support site. 

Expanding the details shows

Done - JCGI return: { "result": "ErrorUnauthorized" }

How can I proceed?

[jeff]

May be related

Linksys EA6350 Factory Install

Hello, I'm trying to install Openwrt on a Linksys EA6350 router. However, when I try to flash the firmware with the factory install OpenWRT binary, the install errors out with a "JCGI return". Not sure what this means! Has anyone seen this before? Any ideas on how to resolve this? Thanks much!

What is the build date of the OEM firmware? If recent, Linksys may have changed it. If so, an older version of OEM firmware may be a work-around.

[rcorre]

Aha! Found the answer at https://community.linksys.com/t5/facebookforums/facebooksingletopicpage/facebook-app/467606153260351/message-uid/823622/tab/board/page/2?nobounce.

My password apparently had some disallowed special characters in it. The Linksys UI will allow you to set such a password, but the firmware flash will fail.

I reset the password to "admin" and was able to flash OpenWRT!

Thanks for looking into this!

[opnrtr]

Thanks for the response! Just to give you some background, I bought this router (used) at a thrift store for the sole purpose of installing and playing with Openwrt...

The firmware version is 1.0.5.182871. I justrecently upgraded from 1.0.4.x in the hope that the upgrade might help. Apparently not!

Anyways, the other post where a forum member changed their password to one without special characters seems worth a try, as mine does have special characters in it! I'll give it a try and report back soon...

Thanks again...