Custom Firmwares do not work on R7800

[Blade]

Hi,

I'm trying to install numerous custom firmwares, but the router just gets stuck in boot-loop. I've tried with both TFTP and uploading via WebGUI.

The only firmwares that for some reason WORK for me are:

• Original NG V1.0.2.63_beta
• Voxel(s) including V1.0.2.73SF
• lede-17.01.6-ipq806x-R7800-squashfs-factory

The FW that get stuck and DO NOT WORK are:

• Latest DD-WRT v3.0 40559
• openwrt-18.06.2-ipq806x-netgear_r7800-squashfs-factory.img
  
• openwrt-18.06.5-ipq806x-netgear_r7800-squashfs-factory
  
• openwrt-19.07.0-rc2-ipq806x-generic-netgear_r7800-squashfs-factory

As far as I can see, there are not many people complaining that they have issues with OpenWRT FW, including my friend who is saying that he even installed openwrt-18.06.2 from WebGUI (he provided his image, that worked for him).

I've noticed that some settings are persisted between flashes - how is this possible. Eg when going from Original to LEDE (configured it from scratch, but for some reason WAN for Static IP did not work) and then back to Original, all the passwords and WIFI settings from Original FW were retained . Could this be causing issues when flashing to Open-WRT Firmwares?
I know that they have increased some partitions. Is there anything that needs to be done for this to flash properly - I've read that only FTPT over Original FW should work (do I need to have it in Factory Settings).

There must be something that is causing issues with DD-WRT and OpenWRT, but on other side works fine with Voxel and LEDE - any suggestions?

I want to try Open-WRT as I cannot get Minidlna working on Voxel, and my WAN on LEDE.


Thanks!

 

[Tom Brough]

Try hnymans r7800 builds, they boot fine on most machines. I've noticed the settings thing too, had openwrt running a week, tftp back to voxel and it was all set up, passwords, wifi, static leases etc....

https://forum.openwrt.org/t/build-for-netgear-r7800/316/1

I have seen reports some newer r7800 machines have a different chipset and are more troublesome to flash.

 

[Blade]

Thanks Tom, actually I've tried OWRT 19.07 from that page.

Should I try one of the masters, as I flashed stable 19.07 (
master-r11887-1de8fc93ca-20200103-ct (ath10k-ct)
master-r11832-c48b571ad7-20191230-ath10k-crashes ("old" mainline ath10k)

Maybe that is what "ath10k-crashes ("old" mainline ath10k)" means .. version for old chipsets? Does anybody know?

 

[Tom Brough]

Ath10k is the wifi driver, it's no longer being updated, so they've moved to canelo technologies for an open sourced updated item known as CT hence the difference.

Latest master would be worth a try.

If not read hnymans threads as there was some discussion before crimbo about someone with a similar problem, and it was due to the chipset change and it needed the file size trimmed slightly.

 

[Blade]

Hi Tom,

I've found a user with similar issue, but unfortunately no closure. His response is 1 year old now.
https://forum.openwrt.org/search?q=thorsten97 topic:316

The second user with same issues was spongioblast
https://forum.openwrt.org/search?q=spongioblast topic:316

He in the end created new Post and managed to get it working via Serial Cable and some image modifications.
https://forum.openwrt.org/t/r7800-flashing-openwrt-causes-bootloop-bad-block-in-kernel-area/49608

The issue appears to be what mk24 describes as:

It appears that OpenWrt requires the rootfs to exist exactly at 16a0000, or it will not find the magic number, can't mount the rootfs, and crashes. Because of skipping a bad block while writing the kernel, the rootfs has been pushed up to 16c0000 in your unit. This happens both with OpenWrt and stock firmware, but again the stock firmware has code to deal with it.​

I'm thinking that since the bad block can be on different locations, we cannot use the same image "fixed" by spongioblast. We would need serial cable (see suggestion in above post) to determine bad block location, "fix" the image and then flash. Looks like once this is done, flashing to other images works fine.

Too much fiddling for me, so I'll just keep using LEDE 17.01.6 :\
Would still like to see an easy solution for defunct R7800, so hopefully someone will crack this.

Thanks all!