After upgrading the firmware, find "Hotmoon Omini" in "Settings"-"Bluetooth"-"My Devices". Click the "!" on the right side and select "Forget This Device". Then go back to "Bluetooth", find "Hotmoon Omini" in "Other Devices", and tap "Connect".
If you cannot find "Hotmoon Omini" in "Other Devices", please turn the "Bluetooth" switch at the top of this page "Off" & "On", and then go to "Other Devices" to find "Hotmoon Omini".