Once logged in via the sticker password, change it to a strong, unique password:
passwd admin
Use a password manager to store it.
Connect via Web UI (port 80) or old Telnet credentials and run: zmm220 default telnet password updated
cat /etc/version
If the output is lower than 2.3.1, proceed with the update.
If you need access, do not search for hacked or leaked backdoor passwords. Instead, follow this professional recovery workflow: Once logged in via the sticker password, change
Step 1: Identify the Current State
Step 2: The Hardware Reset Most ZMM220 devices have a physical reset button (hold for 10-30 seconds during power-on). Warning: This may reset the entire configuration to factory defaults. After a factory reset, the device will temporarily revert to its default password—but only for 5 minutes or until you set a new one. Use a password manager to store it
Step 3: Use Modern Protocols If you only need to monitor or configure the device, avoid Telnet. Use SSH (port 22) if available, or the device’s SNMP interface. Telnet sends every keystroke (including your “updated” password) in plain text—anyone on your local Wi-Fi can sniff it.
Step 4: Consult the Official Documentation Search for “ZMM220 user manual revision 2.0” or later. The manufacturer’s website should have a “Security Advisory” explaining the default password policy change. Common updated default formats include: