I bought RB2011UiAS-2HnD and OS version was 6.43.16.
I have installed mikortik app from google play store and there was a notification to upgrade OS to 6.45.2. accidentally, I clicked this update and now I’m having problem with API authentication (wrong user name and password) with mikrotik.
Is there a way that I can undo this upgrade from mikoritk itself without affecting current users.. i.e. downgrade to the same old version again via terminal or any other way.
Yes, you can download packages for older version, upload them to router and then click Downgrade in System->Packages. But better long-term solution is to fix/upgrade your API client (there were some authentication changes recently), if you don’t want to stay with old RouterOS forever.