So I just tried another card, wich is successfully used in a raspberry pi, with the same result:
U-Boot 2017.05-armbian (Oct 01 2019 - 21:33:07 +0200) for ODROID-XU4
CPU: Exynos5422 @ 800 MHz
Model: Odroid XU4 based on EXYNOS5422
Board: Odroid XU4 based on EXYNOS5422
Type: xu4
DRAM: 2 GiB
MMC: EXYNOS DWMMC: 0, EXYNOS DWMMC: 1
MMC Device 0 ( SD ): 7.4 GiB
Card did not respond to voltage select!
mmc_init: -95, time 12
*** Warning - bad CRC, using default environment
In: serial
Out: serial
Err: serial
Net: No ethernet found.
Press quickly 'Enter' twice to stop autoboot: 0
** Unrecognized filesystem type **
** File not found /boot.ini **
12488 bytes read in 22 ms (553.7 KiB/s)
cfgload addr = 0x50000000, Loading boot.ini from ext4 0:1 /boot/boot.ini
cfgload: applying boot.ini...
cfgload: setenv initrd_high "0xffffffff"
cfgload: setenv fdt_high "0xffffffff"
cfgload: setenv macaddr "00:1e:06:61:7a:55"
cfgload: setenv rootdev "UUID=6418f57a-48d6-474d-9d32-48434f7cd89d"
cfgload: setenv rootfstype "ext4"
cfgload: setenv console "both"
cfgload: setenv verbosity "1"
cfgload: if ext4load mmc 0:1 0x44000000 /boot/armbianEnv.txt || fatload mmc 0:1 0x44000000 armbianEnv.txt || ext4load mmc 0:1 0x44000000 armbianEnv.txt; then env importi
** File not found /boot/armbianEnv.txt **
** Unrecognized filesystem type **
** File not found armbianEnv.txt **
cfgload: if test "${console}" = "display" || test "${console}" = "both"; then setenv consoleargs "console=tty1"; fi
cfgload: if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "console=ttySAC2,115200n8 ${consoleargs}"; fi
cfgload: setenv bootrootfs "${consoleargs} consoleblank=0 loglevel=${verbosity} panic=10 root=${rootdev} rootfstype=${rootfstype} rootwait rw"
cfgload: setenv vout "hdmi"
cfgload: setenv cecenable "false" # false or true
cfgload: setenv governor "performance"
cfgload: setenv ddr_freq 825
cfgload: setenv HPD "true"
cfgload: setenv hdmi_tx_amp_lvl "31"
cfgload: setenv hdmi_tx_lvl_ch0 "3"
cfgload: setenv hdmi_tx_lvl_ch1 "3"
cfgload: setenv hdmi_tx_lvl_ch2 "3"
cfgload: setenv hdmi_tx_emp_lvl "6"
cfgload: setenv hdmi_clk_amp_lvl "31"
cfgload: setenv hdmi_tx_res "0"
cfgload: setenv hdmi_phy_control "hdmi_tx_amp_lvl=${hdmi_tx_amp_lvl} hdmi_tx_lvl_ch0=${hdmi_tx_lvl_ch0} hdmi_tx_lvl_ch1=${hdmi_tx_lvl_ch1} hdmi_tx_lvl_ch2=${hdmi_tx_lvl"
cfgload: ext4load mmc 0:1 0x40008000 /boot/zImage || fatload mmc 0:1 0x40008000 zImage || ext4load mmc 0:1 0x40008000 zImage
5732768 bytes read in 470 ms (11.6 MiB/s)
cfgload: ext4load mmc 0:1 0x42000000 /boot/uInitrd || fatload mmc 0:1 0x42000000 uInitrd || ext4load mmc 0:1 0x42000000 uInitrd
5063530 bytes read in 417 ms (11.6 MiB/s)
cfgload: if test "${board_name}" = "xu4"; then setenv fdtfile "exynos5422-odroidxu4.dtb"; fi
cfgload: if test "${board_name}" = "xu3"; then setenv fdtfile "exynos5422-odroidxu3.dtb"; fi
cfgload: if test "${board_name}" = "xu3l"; then setenv fdtfile "exynos5422-odroidxu3-lite.dtb"; fi
cfgload: if test "${board_name}" = "hc1"; then setenv fdtfile "exynos5422-odroidhc1.dtb"; fi
cfgload: if ext4load mmc 0:1 0x00000000 "/boot/.next" || fatload mmc 0:1 0x00000000 ".next" || ext4load mmc 0:1 0x00000000 ".next"; then echo "Found mainline kernel coi
0 bytes read in 19 ms (0 Bytes/s)
Found mainline kernel configuration
cfgload: ext4load mmc 0:1 0x44000000 /boot/dtb/${fdtfile} || fatload mmc 0:1 0x44000000 dtb/${fdtfile} || ext4load mmc 0:1 0x44000000 dtb/${fdtfile}
63484 bytes read in 71 ms (873 KiB/s)
cfgload: fdt addr 0x44000000
cfgload: if test "${cecenable}" = "false"; then fdt rm /cec@101B0000; fi
libfdt fdt_path_offset() returned FDT_ERR_NOTFOUND
cfgload: setenv bootargs "${bootrootfs} ${videoconfig} smsc95xx.macaddr=${macaddr} governor=${governor} ${hdmi_phy_control} usb-storage.quirks=${usbstoragequirks} ${ext"
cfgload: dmc ${ddr_freq}
cfgload: bootz 0x40008000 0x42000000 0x44000000
Kernel image @ 0x40008000 [ 0x000000 - 0x5779a0 ]
## Loading init Ramdisk from Legacy Image at 42000000 ...
Image Name: uInitrd
Image Type: ARM Linux RAMDisk Image (gzip compressed)
Data Size: 5063466 Bytes = 4.8 MiB
Load Address: 00000000
Entry Point: 00000000
Verifying Checksum ... OK
## Flattened Device Tree blob at 44000000
Booting using the fdt blob at 0x44000000
Using Device Tree in place at 44000000, end 440127fb
Starting kernel ...
The device tries to boot, but after a couple of seconds it restarts and tries again. Somehow it cant start the kernel. Any ideas?