Cannot downgrade from R17, WP76xx, mangoH green

I’ve tried both Windows one-click executable and linux swiflash as well, but when logging to the module I see that both Linux kernel and Legato versions are the same.
The reason for downgrading will be logged in another thread.

Any suggestions ?

It is not recommended to downgrade from r17

I thought this note is for over the air upgrades, can you confirm that it’s not possible to downgrade from R17 to R16.3, or is it just not recommended ?

I think it is not possible
Your test seems prove this