Error in Common Ubiquiti Procedures for XM AirMax devices?

[Alberto Bursi]

On 08/11/21 02:04, Joe Ayers wrote:
> Openwrt Github commit notes, Forum posts, and Documentation, refer to:
>
> "The mtd partitions layout for XM-type devices changed from AirOS v5.5
> to AirOS v5.6. Before installing OpenWrt, downgrade first to AirOS
> 5.5."
>
> reference:  https://openwrt.org/toh/ubiquiti/common
>
> While the documentation is a path to succeed loading openwrt firmware,
> this commit fixed the soft-brick issue (soft-brick meaning tftp
> recovery with serial cable is possible):
> https://github.com/openwrt/openwrt/commit/076d58d3440f382c536ea8874f58b0df23c263bc
>
> It is a key message, that openwrt firmware after this commit, will no
> longer soft-brick the device, not communicated.
>
> The key misunderstanding is around the root cause due to Ubiquiti
> tightening up uboot to further check partition sizes.   The root cause
> was identified as a bad openwrt size definition that older versions of
> uboot accepted, without end user awareness.
>
> The reason I raise this issue is due to users in the
> https//www.arednmesh.org community struggling to downgrade to AirOX
> v5.5, and we spend time working with them only to do tftp
> "hold-reset-button" firmware loads to succeed as quickest path.
>
> Note, however, there are still issues where newer Uboot versions
> expect images to have particular naming conventions, which are also
> addressed in later fixes:
>
> https://github.com/openwrt/openwrt/commit/6009b3fd586a1fd91400074080afb9545c6cf7e2
>
> Thus, firmware before this time will not tftp "hold-reset-button" load
> due to this 2nd issue, but not soft-brick the device.
>
> I've not found the time to track down how to contact the relevant
> stakeholders to address this issue in the documentation, consequently,
> blasting out in this list in hopes of triggering someone to update the
> relevant openwrt documentation to add more clarity to the issue.

The documentation is a wiki and it can be edited by anyone that has 
registered an account.
If you know enough about these particular devices and want to edit that 
page to update the information, please contact me (at this email) or 
tmomas (at tmo26 at gmx.de) in private to get an account, or go through the 
forum.

See the forum thread here about the "new" manual registration of new 
accounts in the wiki
https://forum.openwrt.org/t/applying-for-openwrt-wiki-account/101671

-Alberto