Zyxel NBG6817 Dual Boot Hardware switch


I like to test a possible bug in OpenWRT. For that it would be helpful to know if there is a hardware switch that triggers the alternativ firmware. Did not find anything about this.


Not sure if you are specifically looking for a way to use a hardware switch or just for a way to switch to the alternative firmware. The latter can be done via a Luci package: https://openwrt.org/packages/pkgdata/luci-app-advanced-reboot and see the support thread here: https://forum.openwrt.org/t/web-ui-to-reboot-to-another-partition-for-linksys-zyxel-dual-partition-routers-and-to-power-off-power-down


looking especially for a hardware switch as I have a tagged network and after resetting the router it cannot be accessed anymore. So it would be easier instead connecting it to a laptop and restore a backup, etc.

Advanced reboot is cool and I am using it but it is not helpful if access is lost or it is not installed because of the reset. :slight_smile:

I have never found a ways to trigger firmware failover on the nbg6817, which surely sounds nonsensical, but I'd love to be proven wrong.

  • sysupgrade (as well as the OEM firmware) alternates between both partitions and toggles the dualflag.
  • luci-app-advanced-reboot allows you to toggle this setting from a running system
    • nbg6817-dualboot works on cli, both on OpenWrt and the OEM firmware, offering the same functionality
  • push-button tftp recovery always overwrites the primary partition(-set) and leaves the secondary partition(-set) alone
    • you can exploit this behaviour for experimenting, always experiment on the primary partition(-set) - if push comes to shove, that will be overwritten via push-button tftp recovery; your 'productive' installation/ configuration remains safely untouched on the secondary partition(-set) and can be switched to, once you can use luci-app-advanced-reboot/ nbg6817-dualboot again

But please, if you find another way to toggle the dualflag on a non-booting system (apart from serial console access), please holler and add that information to the wiki.

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The dualboot script I did not know...that would be a good step forward as I can switch the partition without any internet connection easily. A candidate to add to the router specific image that it would be available every time... :slight_smile:

I guess you could combine a button like “wps” to a simple script to toggle the dual boot feature. See https://openwrt.org/docs/guide-user/hardware/hardware.button

Install a “management” vlan into the image could also solve your “reset” problem. Kind of like done with the Netgear managed switch: https://openwrt.org/toh/netgear/gs108t_v3

But: you say test for bugs, so I strongly suggest using the serial console for this and depending the type of bug or crash you can easily “recover” from the console.