Locking yourself out of a security DVR is a common headache for property owners and technicians alike. The AHB8204-HNN is a widely distributed 4-channel digital video recorder board, often manufactured by Xiongmai (XM) and rebranded under dozens of local security labels.
Power cycle the DVR and press any key to interrupt the boot loader into mode.
Attempting to guess the password through exhaustive trial and error.
DVR Model AHB8204-HNN Super Password Cracked: How to Reset and Master Password Generation