I have Descent Mk2i APAC version.
The Garmin Express version 7.8.0.0 running on macOS 11.5.2 has told me that the firmware update of Standard Chinese 2.30 was available since a couple weeks ago. I clicked install on the app and Express showed no more update afterwards. Then I disconnect Mk2i, manual shut down and rebooted it. The same software update was shown again once I connected to the Mac.
I have repeated this connect-install-disconnect-shut-down-reboot cycles a dozen times over this 2 weeks.
How to install the update successfully?