Try cold reboot the device and see if you are able to break into rommon post that. for cold reboot perform below steps: 1) power off the device physically. 2) remove the power cables and wait for 5 mins. 3) replug the power cables and switch on the d...

Kindly check below document for the password-reset for FPR3110 from Rommon: https://www.cisco.com/c/en/us/td/docs/security/firepower/2100/troubleshoot_fxos/b_2100_CLI_Troubleshoot/b_2100_CLI_Troubleshoot_chapter_011.html#task_vxn_r5h_qdb Make sure yo...