Hi,
I tried to find the answer myself, but did not find a similar case in the forum.
I just bougth a S905X with 2Gb RAM from amazon (B01FNWLL9I). (I previously owned a S905/1Gb/gigabit ethernet version, but it is crashing when I try to open a picture folder, with the RAM usage going to 100%, so I decided to replace it with this 2gb version to be able to look at my photos)
The new one is booting ok with the default dtb, but the reported RAM amount is incorrect. It says 1Gb (800Mb to be precise). I checked on Android, and it really have 2Gb. I tried others dtb (all from this page Index of /s905/8.2/device_trees/S905X/), but the box does not boot for any of them. If I put back the original one, i boot again, but using only half of the RAM...
Any soution ? Should I extract my android dtb ? (Is there a tuto for that).
Thank you.