Please see the below for how to recover password of ERS8800/8600
1.Remove backup cpu if present.
2.Reboot the switch from console
Are you sure you want to re-boot the switch (y/n) ? Y
Loaded boot configuration from file /flash/boot.cfg
…
3.Enter Boot monitor mode and issue the command as below
Press to stop auto-boot…
monitor# reset-passwd --> defaulted to default credentials.
monitor# boot
Fyi, Below is from manual.
Resetting passwords to default values
Reset passwords to the default values. You may need to do this if passwords are lost or
compromised.
For information about changing passwords, see Avaya Ethernet Routing Switch 8800/8600 –
Administration, NN46205-605.
Procedure steps
1. Reset the device.
2. Recover the passwords to the default values by using the following boot monitor
command:
reset-passwd