I have a 2921 c2900-universalk9-mz.SPA.150-1.M3.bin , at the beginning was c2900-universalk9-mz.SPA.150-1.M2.bin. I have uck9 and ipbasek9 permanent license. Because of some problems with FXS card I had to change form M2 to M3.
When I try to return to the previuos version I could not do it, the router sent a message about security and went to rommon 1> every time I try to reload it.
any reason about this issue??
I need to return to the previous version because the new one has a bug related with DND softkey