I am using the SpenceKonde / megaTinyCore to program the ATtiny404 using CH340 serial UPDI.
When I click upload, It says
Upload error: A programmer is required to upload
But when I select Upload using programmer, it uploads.
UPDI programming for Arduino using a serial adapter
Based on pymcuprog, with significant modifications
By Quentin Bolsee and Spence Konde
Version 1.2.0 - June 2021
Using serial port COM4 at 460800 baud.
Set fuses: ['2:0x02', '6:0x04', '8:0x00']