Adding OpenWrt support for Zyxel VMG4005-B50B

Hi, I recently got my hands on a Zyxel VMT4005-B50B VDSL modem. The hardware runs on a Broadcom BCM63138 SOC. I see some people have worked on ports in the past with little success, and I was wondering how I could help get OpenWRT ported to this device.

There is a UART on the board, and connecting to it I can see the bootup process with the CFE bootloader. I'm not sure how to get further to tell it to boot a TFTP image, it looks like it requires setting some magic bits or flags to enable booting from a TFTP image. I did find the command to flash an image over TFTP, but I wanted to make sure there's a working image first before I commit to flashing.

You do realize that even if the device would get OpenWrt support to the maximum extent possible, that its xDSL modem feature is never going to be supportable? Acknowledging this, what would be left?!

If I interpret https://www.zyxel.com/us/en/products_services/VDSL2-17a-Bonding-and-35b-Single-Line-Bridge-VMG4005-B50B/ correctly, this device has one xDSL port and one ethernet port, no wifi (which wouldn't be supportable), no FXS (which wouldn't be supportable), no DECT (which wouldn't be supportable either) - what's left to be usable? Wired router usage would require at least two ethernet ports (unless you use VLANs and an external managed switch, but, honestly, why bothering about this device for that topic). It doesn't have USB ports, so light server uses aren't an option either and I don't think there'd be much in the sense of GPIO, I²C, SPI I/O - at least nothing that would compete with an RPi-0W.

So what would you expect from this device running OpenWrt, other than being an (almost) useless design piece chugging power out of the wall?

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What would be needed to get the xDSL interface working? I have a DM200 that runs OpenWRT, and would like to replace it with this modem. I need OpenWRT running on it, or another interface so I can run wpa_supplicant on the modem to authenticate against my DSL provider.

Broadcom to publish GPL2 compliant xDSL drivers, which is not going to happen.

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Oh, I see what you mean. Thanks for the update.