Suddenly only 1/4 the RAM [1GB model shipped as 4GB]

[ejolson]

Since the system had a Sandisk SSD plugged into the USB3 socket I decided to remove that to see if that helped.  Unfortunately, the system still boots up with only 1GB out of 4GB RAM detected.  The early dmesg boot lines of the second system which is missing 3GB of RAM look like

Code:

[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd034]
[    0.000000] Linux version 5.8.6-rockchip64 (root@desktop) (aarch64-none-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 9.2.1 20191025, GNU ld (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 2.33.1.20191209) #20.08.2 SMP PREEMPT Fri Sep 4 20:23:22 CEST 2020
[    0.000000] Machine model: Pine64 Rock64
[    0.000000] efi: UEFI not found.
[    0.000000] cma: Reserved 128 MiB at 0x0000000034c00000
[    0.000000] NUMA: No NUMA configuration found
[    0.000000] NUMA: Faking a node at [mem 0x0000000000200000-0x000000003fffffff]
[    0.000000] NUMA: NODE_DATA [mem 0x3fdc3100-0x3fdc4fff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000000200000-0x000000003fffffff]
[    0.000000]   DMA32    empty
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000200000-0x000000003fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000200000-0x000000003fffffff]
[    0.000000] On node 0 totalpages: 261632
[    0.000000]   DMA zone: 4088 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 261632 pages, LIFO batch:63
[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv1.0 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: MIGRATE_INFO_TYPE not supported.
[    0.000000] psci: SMC Calling Convention v1.0
[    0.000000] percpu: Embedded 32 pages/cpu s93528 r8192 d29352 u131072
[    0.000000] pcpu-alloc: s93528 r8192 d29352 u131072 alloc=32*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[    0.000000] Detected VIPT I-cache on CPU0
[    0.000000] CPU features: detected: ARM erratum 845719
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 257544
[    0.000000] Policy zone: DMA

while the dmesg output of the first system that detects all 4GB RAM reports

Code:

[    0.000000] Booting Linux on physical CPU 0x0000000000 [0x410fd034]
[    0.000000] Linux version 5.7.15-rockchip64 (root@desktop) (gcc version 9.2.1 20191025 (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)), GNU ld (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10)) 2.33.1.20191209) #20.08 SMP PREEMPT Mon Aug 17 00:26:28 CEST 2020
[    0.000000] Machine model: Pine64 Rock64
[    0.000000] efi: UEFI not found.
[    0.000000] cma: Reserved 128 MiB at 0x00000000f3c00000
[    0.000000] NUMA: No NUMA configuration found
[    0.000000] NUMA: Faking a node at [mem 0x0000000000200000-0x00000000feffffff]
[    0.000000] NUMA: NODE_DATA [mem 0xfe7c8100-0xfe7c9fff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x0000000000200000-0x000000003fffffff]
[    0.000000]   DMA32    [mem 0x0000000040000000-0x00000000feffffff]
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000200000-0x00000000feffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000200000-0x00000000feffffff]
[    0.000000] On node 0 totalpages: 1043968
[    0.000000]   DMA zone: 4088 pages used for memmap
[    0.000000]   DMA zone: 0 pages reserved
[    0.000000]   DMA zone: 261632 pages, LIFO batch:63
[    0.000000]   DMA32 zone: 12224 pages used for memmap
[    0.000000]   DMA32 zone: 782336 pages, LIFO batch:63
[    0.000000] psci: probing for conduit method from DT.
[    0.000000] psci: PSCIv1.0 detected in firmware.
[    0.000000] psci: Using standard PSCI v0.2 function IDs
[    0.000000] psci: MIGRATE_INFO_TYPE not supported.
[    0.000000] psci: SMC Calling Convention v1.0
[    0.000000] percpu: Embedded 32 pages/cpu s92568 r8192 d30312 u131072
[    0.000000] pcpu-alloc: s92568 r8192 d30312 u131072 alloc=32*4096
[    0.000000] pcpu-alloc: [0] 0 [0] 1 [0] 2 [0] 3
[    0.000000] Detected VIPT I-cache on CPU0
[    0.000000] CPU features: detected: ARM erratum 845719
[    0.000000] Built 1 zonelists, mobility grouping on.  Total pages: 1027656
[    0.000000] Policy zone: DMA32

The first difference between the two machines is the cma memory address.  What's that? Also, is the lack of DMA32 zones the result of less memory being detected or the cause?  Is there a way to test memory using the uboot environment to see what's wrong?

Is there any firmware on the board that needs to be reset?