Built_from_SD_card_direct_download,  https://support.criticallink.com/redmine/projects/mityarm-5cs/wiki,  5CSX-H6-42A	5CSX-H6-42A SD Card

lsblk output:

sdc      8:32   1  28.9G  0 disk 
├─sdc1   8:33   1   256M  0 part        <----------  I cannot access this area to write the .rbf (if that's what I have to do)
├─sdc2   8:34   1     1M  0 part 
└─sdc3   8:35   1   762M  0 part /media/john/rootfs

Boot output:

U-Boot SPL 2023.07-rc6-ge64596af4c-dirty (Aug 05 2024 - 17:12:19 +0000)
DDRCAL: Scrubbing ECC RAM (1024 MiB).
DDRCAL: SDRAM-ECC initialized success with 612 ms
MPU           800000 kHz
DDR           400000 kHz
EOSC1          25000 kHz
EOSC2          25000 kHz
F2S_SDR_REF        0 kHz
F2S_PER_REF        0 kHz
MMC            50000 kHz
QSPI          400000 kHz
UART          100000 kHz
SPI           200000 kHz
Trying to boot from MMC1


U-Boot 2023.07-rc6-ge64596af4c-dirty (Aug 05 2024 - 17:12:19 +0000) Critical Link MitySOM-5CSx

CPU:   Altera SoCFPGA Platform
FPGA:  Altera Cyclone V, SE/A6 or SX/C6 or ST/D6, version 0x0
BOOT:  SD/MMC Internal Transceiver (3.0V)
DRAM:  1 GiB
Core:  35 devices, 19 uclasses, devicetree: separate
MMC:   dwmmc0@ff704000: 0
Loading Environment from MMC... OK
In:    serial
Out:   serial
Err:   serial
Model: MitySOM-5CSX-H6-42A Altera SOCFPGA Cyclone V
BOARD: Critical Link MitySOM-5CSx Module
Net:   eth0: ethernet@ff702000
gpio: pin 0 (gpio 0) value is 1
Hit any key to stop autoboot:  0
5399528 bytes read in 270 ms (19.1 MiB/s)
23316 bytes read in 4 ms (5.6 MiB/s)
Failed to load '/dev_5cs.rbf'                        <----------------  This is not on the image.
Command 'load' failed: Error -6
Kernel image @ 0x100000 [ 0x000000 - 0x5263e8 ]
## Flattened Device Tree blob at 00000100
   Booting using the fdt blob at 0x000100
Working FDT set to 100
   Loading Device Tree to 3af3b000, end 3af43b13 ... OK
Working FDT set to 3af3b000

Starting kernel ...

Deasserting all peripheral resets