first install / debricking / restore stock:
0. Have a PC running a tftp-server @ 192.168.1.99
connect the PC to any LAN-Ports
put the openwrt...-factory.bin (or V1.00(ABCT.X).bin for stock) file
into the tftp-server root directory and rename it to just "ras.bin".
power-cycle the router and hold down the the WPS button (for 30sek)
Wait (for a long time - the serial console provides some progress
reports. The u-boot says it best: "Please be patient".
Once the power LED starts to flashes slowly and the USB + WPS LEDs
flashes fast at the same time. You have to reboot the device and
it should then come right up.
But still after 30 min only power led is flashing and usb led is lit up all the time.
I´m not connected to serial console, so I cant see progress - should I wait more then 30 min?
If I power off and on, then it just boot original firmware.
TFTP server says upload is suscesful every time I try.
Try to put an unmanaged switch between your router and the tftp server, extrapolating from my experiences with the nbg6817, the tftp window is very small (3s) and link training might take too long - a switch keeps the link to your computer up, even if the router is powered off or rebooting, and might give you some crucial time.
I guess you would need to attach a serial console, in order to see what the device is doing. It could be something related to the tftp-server you are using, some have problems with the "binary" mode... I'm using the standard tftpd-hpa server that comes with debian (sid) 5.2+20150808-1+b1.
But... you might as well not bother with tftp. Because David Bauer decided to change the image creation code for the the official openwrt snapshot factory.bin images to make it possible to flash them via the web-interface on the stock firmware. Just follow the steps under the "Installation via Web-UI" topic.
(Never tested it myself though, but I think you can write him a mail, if you run into any issue with the web-ui flash.)
This is the file I downloaded (and renamed to ras.bin) ras.bin
Both router where on org. firmware V1.00(ABCT.6)C0 I tried downgrade to the oldest one V1.00(ABCT.5)C0
(October 27, 2017) stil no luck in Zyxel web gui or tftp - I have tried 3 different tftp software, and all of the made it to 100% every time.
so it's clear that the builder hit a problem in the make-ras.sh's to_be32. The question is what's the cause? A incompatible bash interpreter, or an obsolete bash? @jow (can you tell me what the distro + packages the slashdirt builder
As for a fix: I did update the make-ras.sh script in my LEDE-IPQ40XX (the OpenWrt version is older) a while long ago (maybe 2-3 month now?) to address issues that came up when I was testing the script with OpenWrt's busybox and goodol' Mac OS X 10.5' bash.
I opted to integrate the to_be32 and append_bin into a new append_be32() that worked on all DUTs.
This morning powering NBG6617 backup it had returned to ZyXEL's firmware.
I flashed the factory upgrade firmware provided by David Bauer using tftp server - and the router works with openwrt, I did my setting, and I pulled power for 12 mins, and this time it loaded openwrt like it should.
Is this one of them routers that need double firmware upgrading for it to stick?