This started when I upgraded a routerboard from 3.26 to 3.27. When I upgraded the OS, I also upgraded the firmware to 2.20 (I believe it was 2.18 before that). Everytime I tried to telnet with the "system telnet" command, the router would lock up. I would have to reboot it multiple times to get'er back online. In Any case, I replaced the router (oh, these are RB493AHs) with another with 3.27 OS but still firmware 2.18. I have not yet had a problem with the replacement.
Now, this other one I have to hold in the button on the from in order to get it to boot (I understand that bypasses the newest firmware or something?) but once in I cannot seem to revert the firmware. My console is also unresponsive. I've tried system reset, and sill cannot get in with any baudrate. I'm using a Xserial cable that I use for any other mikrotik.
Any tips on getting this firware reverted?
Also, any updates to address this problem- or am I the only one with it
Thanks for the help-