the_collector

Glad you went a step further.
This looks definitely a new board I never dealt with.
 
The multitool sources are available on my repository https://github.com/paolosabatino/multitool
However if you can boot the multitool from the USB stick you can get a shell and look into dmesg for further details, like for example if the emmc and sdcard are seen by the kernel, it's a starting point to understand why u-boot does not detect the sdcard.
 
You should also be able to interrupt the u-boot bootstrap and use it's interactive shell to get further info about the mmc subsystem. Commands like mmc info and mmc list should be useful to start with. U-boot shell has its own shell commands, but you should be easily find them somewhere on the net.
 
 

I'm having an issue getting the multitool SD card image to run on my RK3229 nand board, hoping someone may be able to help.
 
Dumps below from the UART interface (two separate boots of the same image to capture initial SoC output at 1500000 baud and armbian output at 115200 baud.
 
In 300MHz DDR3 Bus Width=32 Col=10 Bank=8 Row=15 CS=1 Die Bus-Width=16 Size=1024MB mach:2 OUT Boot1 Release Time: 2016-03-15, version: 2.31 ChipType = c 276 No.1 FLASH ID:ad de 14 a7 42 4a ECC:60 SdmmcInit=0 0 BootCapSize=0 UserCapSize=39c6000 FwPartOffset=2000 , 0 StorageInit ok = 520688 SecureMode : SBOOT_MODE_NS Loder code check ok! theLoader 0x61000000, loadaddr: 0x2000 Loder code check ok! theLoader 0x68400000, loadaddr: 0x4000 INF [0x0] TEE-CORE:init_primary_helper:377: Initializing (1.1.0-297-ga4fd2d1 #1 Thu May 17 10:22:22 UTC 2018 arm) INF [0x0] TEE-CORE:init_primary_helper:378: Release version: 2.0 INF [0x0] TEE-CORE:init_primary_helper:379: Next entry point address: 0x61000000 INF [0x0] TEE-CORE:init_teecore:83: teecore inits done  
U-Boot 2020.01-armbian (Apr 15 2020 - 12:30:37 +0000) Model: Generic Rockchip rk322x TV Box board DRAM: 1010 MiB MMC: dwmmc@30000000: 1, dwmmc@30020000: 0 Loading Environment from EXT4... Card did not respond to voltage select! In: serial@11030000 Out: serial@11030000 Err: serial@11030000 Model: Generic Rockchip rk322x TV Box board rockchip_dnl_key_pressed: adc_channel_single_shot fail! Net: eth0: ethernet@30200000 starting USB... Bus usb@30040000: scanning bus usb@30040000 for devices... 1 USB Device(s) found scanning usb for storage devices... 0 Storage Device(s) found stopping USB.. starting USB... Bus usb@30040000: scanning bus usb@30040000 for devices... 1 USB Device(s) found scanning usb for storage devices... 0 Storage Device(s) found Hit any key to stop autoboot: 0 Card did not respond to voltage select! Device 0: unknown device Card did not respond to voltage select! Speed: 100, full duplex BOOTP broadcast 1 BOOTP broadcast 2 BOOTP broadcast 3 DHCP client bound to address 192.168.1.145 (1005 ms) *** ERROR: `serverip' not set Cannot autoload with TFTPGET missing environment variable: pxeuuid missing environment variable: bootfile Retrieving file: pxelinux.cfg/01-52-7d-88-b9-f6-2c Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A80191 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A8019 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A801 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A80 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A8 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0A Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C0 Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/C Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/default-arm-rk322x-rk322x-box Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/default-arm-rk322x Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/default-arm Speed: 100, full duplex *** ERROR: `serverip' not set missing environment variable: bootfile Retrieving file: pxelinux.cfg/default Speed: 100, full duplex *** ERROR: `serverip' not set Config file not found Speed: 100, full duplex BOOTP broadcast 1 DHCP client bound to address 192.168.1.145 (5 ms) *** ERROR: `serverip' not set Cannot autoload with TFTPGET Speed: 100, full duplex BOOTP broadcast 1 DHCP client bound to address 192.168.1.145 (4 ms) *** ERROR: `serverip' not set Cannot autoload with TFTPGET =>