I've found this article and tried to run Brunch with chromeos_15662.88.0_zork_recovery_stable-channel_mp-v9.bin on my 7840HS. To my surprise the old chromeos version 120 works - the only issue I've noticed - google drive content in Files didn't work. It even worked with the latest 144 version of Brunch (but with broken Android). Then I've updated ChromeOS to the latest version 145, but the system started to reboot after few minutes since logon. I was able to downgrade it to version 144 with PWA, but after that I had login problems. Anyway, just share my experience, maybe it will be useful.
I've found this article and tried to run Brunch with chromeos_15662.88.0_zork_recovery_stable-channel_mp-v9.bin on my 7840HS. To my surprise the old chromeos version 120 works - the only issue I've noticed - google drive content in Files didn't work. It even worked with the latest 144 version of Brunch (but with broken Android). Then I've updated ChromeOS to the latest version 145, but the system started to reboot after few minutes since logon. I was able to downgrade it to version 144 with PWA, but after that I had login problems. Anyway, just share my experience, maybe it will be useful.