Thanks @azvarel . The video mode conf works! If you want to modify manually:
Connect to your Recalbox via SSH:
ssh root@recalbox
Edit file recalbox.conf:
mount -o remount,rw /
vi recalbox.conf
replace:
global.videomode=CEA 4 HDMI
with:
global.videomode=default
Exit saving (:wq! ENTER)
Restart Recalbox:
shutdown -r now
For me, this is an issue during upgrade. It seems the upgrade process doesn´t take into account if you are using an external hard-drive for the game library, updating the files in the SD card but not in the external drive.
Please, review carefully for the next launch (4.1)