Archer C7 AC1750 v5 bricked?

I was using this router with openwrt 18.06.2.
Recently while installing kmod-hwmon-vid the router immediately freezed.
So I power cycled the router and the power led went from fixed on to fast blinking to slow blinking and then after a couple of seconds all the leds were powered on and the router immediately rebooted.
Reinstalling through TFTP in recovery mode doesn't work because it seems that the router doesn't query for any tftp server on the network nor it does any network activity nontheless. Does this mean that the router is hard bricked?
Do you think that trying to flash through serial connector would be an option or a completely waste of time?

many thanks,
goo

Try FailSafe Mode.
Here's some documentation incase you need it.
https://openwrt.org/docs/guide-user/troubleshooting/failsafe_and_factory_reset

Unfortunately it didn't work. The router seems to enter failsafe mode as it doesn't reboot anymore (power led remains fast blinking), but it is still not accessible from remote and the led of the lan port doesn't transition to on.

Did you make sure to change your clients IP address to "192.168.1.x"?
And if you are saying that the LAN ports on the back aren't working? Have you tried them all? Maybe it's buggy.

You pointed me in the right direction!
I mistakenly configured the IP address as /32. After changing it to /24 I finally managed to ssh to the router in failsafe mode.
From there I deleted /etc/modules.d/hwmon-sch5627 (not hwmon-vid that I initially thought it was the cause of the system freeze), rebooted and the router normally booted again.
Maybe kmod-hwmon-sch5627 might be removed from the packages for this particular device.
Anyway I can say it is solved.
Thank you very much

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You might want to file a bug report or send email to OpenWrt-devel if you find that the kmod is truly causing a crash. While some of the core devs read the forum, many do not.

In this particular case, I don't think there is a whole lot possible to change from OpenWrt's side. Kernel and kernel modules are common for the whole target, it's not possible to exclude them for a particular device (overly restrictive target whitelists for kmods are usually more problematic for users and developers alike) and the problematic package in question is not preinstalled or part of the default DEVICE_PACKAGES, so it had to actively installed. If kmod-hwmon-sch5627 makes sense on ar71xx/ ath79 in general or the archer c7-v5 in particular is another question, personally I doubt it (an I²C based watchdog driver for SMSC SCH5627/ SCH5636 superio-s), but it basically boils down to, "if it hurts, don't do it".

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