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ZD-series
Holding down the button in for two seconds will load defaults but keep the network setup.
Please see the full guide here https://wwwdocs.zebra.com/content/tcm/us/en/support-downloads/knowledge-articles/ait/ZD620-ZD420-Factory-Resetprinters/desktop/zd421-and-zd621-desktop-printers-user-guide/tools/printer-diagnostics/reset-button-functions.html
ZQ-series
To reset a Mobile printer, you need to send a file containing the reset commands to the printer.
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