Из сервисного мануала:

Network reset

A network reset changes all network system parameters in NVRAM to the factory defaults. During
the network-reset process, all button presses are ignored.
Use the following procedure to perform a network reset.
1. Turn off the printer.
2. Press and hold the Job Cancel button.
3. Turn on the printer and continue to hold the Job Cancel button for approximately 10 seconds,
but no longer than 20 seconds. During this process, the Attention light turns on.
4. Release the Job Cancel button. The Attention, Ready, and Go lights begin cycling from front to
back. After the network-reset process is complete, the device returns to the ready state.
NOTE If the Attention and Ready lights illuminate before you release the Job Cancel
button, start again at step 1.

Cold reset

A cold reset changes most system parameters in NVRAM to the factory defaults. However, unlike
NVRAM initialization, a cold reset does not reset the page count, the paper tray sizes, language, or
formatter number.
NOTE A cold reset also resets all the HP Jetdirect settings as well as the printer settings.
Use the following procedure to perform a cold reset.
1. Turn off the printer.
2. Press and hold the Go button.
3. Turn the printer on, and continue to hold the Go button for at least 5 seconds, but not longer
than 15 seconds. During this process, the Attention LED turns on.
4. Release the Go button.
NOTE If both the Attention and the Ready LEDs turn on before you release the Go
button, you must start the procedure again with step 1.
The printer's LEDs begin cycling. The cold-reset process runs until completion, and the printer
returns to the ready state.

NVRAM initialization

CAUTION Only perform the following procedure if absolutely necessary. Performing an
NVRAM initialization resets some parameters that cannot be restored later.
NVRAM initialization sets all default variables stored in NVRAM back to factory default values or to a
default ROM value, depending on the variable. It also performs a system reset.
NVRAM initialization resets the following:
● All menu settings to factory default values
● Factory settings such as formatter number, page counts, and factory paper settings
Use the following procedure to perform an NVRAM initialization.
1. Turn the printer off.
2. Press and hold down the Go button.
3. Turn the printer on, and continue to hold the Go button for at least 20 seconds. During this
process, the Go button, Attention, and Ready LEDs each turn on.
4. Release the Go button.
The printer lights begin cycling. After the NVRAM initialization is complete, the printer returns to the
ready state.

Super NVRAM initialization

This feature is similar to NVRAM initialization, except all of NVRAM is re-initialized (including the
configuration parameters not reset by an NVRAM initialization).
Use the following procedure to perform an NVRAM initialization.
1. Turn off the printer.
2. Press and hold the Go button.
3. Turn on the printer and continue to hold the Go button for at least 50 seconds. During this
process, the Attention, Ready, Go lights turn on. Then the Attention and Ready lights turn off,
leaving only the Go light illuminated.
4. Release the Go button. The Go, Ready and Attention lights turn on.
5. Press and hold the Go button. All lights turn off. During the next three seconds, the Go, Ready
and Attention lights turn on in that order, one per second.
6. Release the Go button to perform the initialization. The control panel lights begin cycling from
front to back. After the Super NVRAM initialization process is complete, the printer returns to the
ready state.

Proceed with caution; when you do nvram resets, it will also remove page count and formatter number, etc.