Thank you.
Probably this is one of the reasons for poor perfomance of n64 in pi4.
And dreamcast have the same problem with the videomode.

Would be interesting for testing, that someone with a pi4 or rpi400 do the videomode change test with n64 and dreamcast to see if it works, checking always the final resolution in tv or monitor, and if works post the options used.

Hopefully the new version will be soon.

Sorry, but:
I deleted ONLY the semicolon --> not work
With the semicolon, and THEN adding the new lines --> not work

The default options :
n64.videomode=DMT 4 HDMI
dreamcast.videomode=DMT 4 HDMI and DMT 9 HDMI
--> not work

Tried a lot of DMT and CEA modes --> not work
Add hdmi_group=1 in config.txt for CEA modes --> not work
Add hdmi_group=2 in config.txt for DMT modes --> not work

My english is bad, maybe we aren't understand each other.
There is someone that have tried to change the videomode and is working checking the real output resolution on the tv or the monitor?

Thanks @Zing, but I i had deleted the semicolon and doesn' t work, and I have added the lines at the file bottom and nothing, always 1080p output.
I thought that the global.videomode option is for all emulators... then why doesn't work with n64 and dreamcast?

Hello.
I have a raspberry pi 400 with recalbox 7.1.1. I can't change the output resolution for the n64 and dreamcast emulators.
I have put the n64.videomode and dreamcast.videomode lines in recalbox.conf with various options, but the output is always 1080p.
If i put global.videomode=CEA 4 HDMI in recalbox.conf, then the output is 720p for the rest of emulators...but n64 and dreamcast are still at 1080p. What am I doing wrong?