I got flashrom on OpenBSD working with a USB ch341a programmer:

nano:~$ doas flashrom -p ch341a_spi -v goose
flashrom v1.6.0 on OpenBSD 7.8 (amd64)
[..]
Found Unknown flash chip "SFDP-capable chip" (16384 kB, SPI) on ch341a_spi.
Verifying flash... VERIFIED.