The buzzing sound is present on both versions (PAL & NTSC).
MDMA, UDMA settings are blind spot because other devices will not use it.
It may only works for HDD.
Unfortunately it is not working with my config.
Other solution that works previously was cold boot -> E1 launch keys.
But I think currently this "method" is not working.
I can't find with what OPL rev this "solution" worked.
I rather enable PS2 logo, wait a bit longer to get rid of this annoying sound.
Are you using FHDB perhaps??