I don't know if this is strictly the correct forum. Mods, please move if not.
I have an Archer C2600 v1.0 and have managed to install 19.07.5 on it using TP-Link WebUI -> 22.214.171.124.factory.img, OpenWRT CLI sysupgrade -> 126.96.36.199.sysupgrade.img, Luci sysupgrade -> 188.8.131.52.sysupgrade.img and TFTP -> 184.108.40.206.factory.img. All no issues, as long as I stick with release.
My problem is installing/booting snapshot builds. I have tried various snapshot builds from 2020-12-20, 2020-12-24 and 2020-12-28. None of these builds will boot. I've tried going from TP-Link WebUI -> snapshot.factory.img, OpenWRT 19.07.5 Factory.img Luci -> snapshot.sysupgrade.img (both with keep settings and not), TFTP -> snapshot.factory.img, OpenWRT 19.07.5 CLI sysupgrade from factory.img -> snapshot.sysupgrade.img, and OpenWRT 19.07.5 CLI sysupgrade from sysupgrade.img -> snapshot.sysupgrade.img
I am keen to try snapshot as I would like to try using DAWN, which currently only has packages available for snapshot images. My D-Link DIR-882 is on snapshot by default and will load DAWN no problems at all.
In all of the above attempts I have hit the same problem. The router reboots/bootloops constantly. It starts with the internet light coming on orange + solid for about 3 seconds, then all lights come on white + solid for about 3 seconds, then all lights off for about 3 seconds and it loops. I have left it for up to 5 hours.
I have run Wireshark and post snapshot install, the router sends regular ARP requests looking for who has 192.168.0.66, similar to the TFTP recovery, but it stops short of looking for a TFTP server and just keeps looking for that IP indefinitely. I have set my PC to static 192.168.0.66, mask 255.255.255.0 and even with TFTPD64 running a DHCP server, it gets replies from my PC, but doesn't try to get DHCP, nor does it try to do a TFTP transfer, just looking for the IP repeatedly.
I can always do TFTP recovery by holding reset either as I turn it on, or as it bootloops. I can always reboot to 19.07.5 without problem post TFTP recovery. I can use Wireshark to watch that it does quite different things once it kicks into TFTP mode, fetching the image, then loading, rebooting and then it switches to 192.168.1.1 and I can reconfigure my Ethernet card to DHCP and pick up an IP Address OK.
Since I have tried going from both the 19.07.5.factory.img -> snapshot.sysupgrade.img and 19.07.5.sysupgrade.img -> snapshot.sysupgrade.img and also TFTP -> snapshot.factory.img from both TP-link firmware and OpenWRT, and also back to 19.07.5 many times, I am pretty confident the router is OK. All attempts to go to snapshot have shown exactly the same result (bootloop, same light patterns, bootloop, rinse and repeat). I have also noted that changes to the kernel partition from 2Mb -> 4Mb occurred in source in 2018, so I don't think that plays into it, since every version I have ever installed will have those changes already built in.
Installing 19.07.5 seems to do the same pattern of lights to a point, but instead of boot looping back to an orange internet light then all lights on and repeat, it reboots only once to the orange internet light, then a flashing white power light, which seems to be the actual boot sequence and then boots the router fully to a constant white power light and ethernet light.
I therefore suspect a problem with the snapshot images themselves.
Any thoughts or suggestions?