FPR2100 unable to log in after upgrading firmware

[Smile丶]

After I upgrade new firmware(ftd-fp2k.6.6.7-223.zip),I can not log in firepower with username and password default.Are there somebody can help me?

FTD loading so long and after that it reboot ,reboot so many times.

Now I cannot log in to the device. What should I do if I want to reinstall the software?

[manabans]

Perform a Complete Reimage
This procedure reformats the entire system, erases the images, and returns it to its factory default settings. After performing this procedure, you must download the new software images and reconfigure your system.

Reference: 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_uzp_kv1_hbb 

[Smile丶]

Thanks for your reply.I have seen the link you shared to me,there are so many way to reimage,which should I choose? I can not log in the device,should I get into the Rommon mode?

[manabans]

You can choose the procedure under the topic 'Perform a Complete Reimage'
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_uzp_kv1_hbb

[Smile丶]

Thanks！Another small question, do I have to subscribe to DNA when I buy Cisco switches?Can I not subscribe?