Existing fire system and error shown in pictures indicating. please advise on what to do next.
If I keeps looping that startup sequence, then the panel is likely toast. Check to make sure the keypad/display is seated properly to the main board. Ensure no ribbon cables or harnesses are hanging loose and not connected.
Disconnect the battery and turn off the supply power. Wait five minutes, then restore power.
i checked those things you mentioned all good. but still error.
Try power cycling as suggested above. If that doesn’t work and it keeps bootlooping, safe to say that panel’s dead.