There's something new.
I've tested the last firmware 2403 pretending to :
1. improve system performance and compatibility
2. improve system stability
3. improve DRAM compatibility
Well, just after updated it : I was unable to boot and I got a yellow/orange light on the motherboard : this error led code means there is a problem with RAM. Then my computer endlessly boots, and shuts down. It's a bootloop and I was stucked !
Panic time ! Because I wonder how will I do to solve this ? With this boot loop I don't even get the POST message... nothing.
I tried to put another couple de RAM from another computer, same thing...
I remembered the USB FLASHBACK on the mobo panel ! I've downloaded the previous safe version of the firmware 2201 ans installed it on the appropriate USB FLBK port. Then I kept the button pressed for 3 seconds (as described on the manual) and that way the flash process began. I was able to roll back to my previous firmware.
Conclusion : this firmware, instead of "improving" compatibility, is just DECREASING it !
Well, not really surprised from ASUS... as they release every time unfinished mobos with a lot of problems.
My next mobo will sure not be an Asus one... No more...
I wanted to share my experience here, maybe it will be beneficial to some in the same situation as me...