Would not recommend installing OpenWrt on any routers with the MT7621/MT7615N combination, due to known 5 GHz Wifi problem.
e.g. DIR-878, DIR-882, DIR-2640...
Not uncommon for devices connecting to above routers via 5 GHz WiFi to display the following error:
Connected, no internet.
Connection to the router is fine/excellent but trying to open a webpage resulting the following error:
Address Not Found
According to lukasz92:
This problem is as old as mt76 driver; will not be fixed.
Problem was definitely present in all the recent 22.03.0 RC releases, except RC6?
Problem is definitely still present in the Stable 21.02.3, 21.02.5 releases.
For those who do not have time/interest going through this entire thread,
The release - *now deleted by arinc9 appears to avoid the 5 GHz WiFi problems and increases routing performance.
EDIT: With the removal of arinc9 releases, Snapshots appear to have least amount of problems.
Note: As of August 21, 2022, hauke has applied arinc9's patch into master = Snapshots as of that date should include the patch.
With that said,
arinc9 deleted the mt7621-dts-work branch August 24, 2022.
The current 22.03.x stable releases do not include all of arinc9's patches.
A quick summary as of September 2022,
Update: As of December 2022, the 5 GHz error messages using snapshots appears to have disappeared however now performance appears to have dropped significantly. e.g. Opening a sample website via 2.4GHz takes 10 seconds but approximately 45 seconds via 5GHz for same website.
Update: January 03 - 13, 2023, encountered multiple unscheduled LAN loss/soft reboots? with snapshots. No messages in system log.
Tested January 16 snapshots using Firmware Selector, ̶a̶p̶p̶e̶a̶r̶s̶ ̶t̶o̶ ̶b̶e̶ ̶b̶a̶c̶k̶ ̶t̶o̶ ̶n̶o̶r̶m̶a̶l̶.
LAN loss/soft reboot? again.
Back to 2022-12-12 snapshot.
For those who do not have snapshot releases from early December 2022 saved.
The 22.03.3 Stable release appears to have least amount of problems as of January 2023. But, expect a loss in performance since it does not include arinc9's patches.