Manjaro-arm with eMMC but only 700M+ RAM available

I’m using Manjaro-arm 22.04(Manjaro-ARM-gnome-rockpi4b-22.04.img) on Rock-pi 4B+(4+64) on eMMC,but here is only 700M+ memory available. This situation is similar to With eMMC ony half of RAM available

Take a picture of the ram chip on your board, and if you have serial console, send the low level serial console log.

Thanks for your reply. Both of ram chips are SKhynix H9HCNNNBKUML XANEE. I don’t have USB to TTL serial cable

However, last time I used SD with Ubuntu 20.04, the ram is 4G(perhaps) available

I have no idea about rockpi4b+

Can’t remember having that device supported in mainline kernel.

If you have 4gb on official os then it must be a difference in the hardware and the dts you’re using on manjaro.

Does Manjaro’s U-Boot use rockchip miniloader instead of U-Boot’s SPL? From our experience U-Boot’s memory initialization code is far inferior to miniloader.

No we don’t use miniloader.
Only upstream uboot with spl.

Thanks for all your replies. Today I turned on rockpi4b+, then I found available RAM turned to be 1.45G, then I rebooted it, RAM came to be 3.41G?! That’s confusing.

The available RAM seems to be random😥Every time it changes to another value.

Install one Radxa image with vendor u-boot and test:

I don’t know much about u-boot. Do you mean boot the OS image from uSD? I tried this but the available RAM is still 1.44G…Then I rebooted it became 1.19G…

Changed to Ubuntu finally. The RAM is 3.77G which is normal.