Correct setup for u-boot and fstab ? Device not booting

[as365n4]

make -j15 CROSS_COMPILE=aarch64-linux-gnu- BL31=bl31.bin all u-boot.itb

This line results in an error message and compiler aborts.

After reading the Build section here --> https://linux-sunxi.org/U-Boot I figured that it should be

make -j15 CROSS_COMPILE=aarch64-linux-gnu- BL31=bl31.bin

and it compiled, altough with a yellow warning at the end.

U-Boot is working and even Ethernet works, but it wont accept my extlinux.conf for some reason....
I think it has something to do with the eMMC-Module

Code:

U-Boot SPL 2021.01 (Jan 18 2021 - 11:23:42 +0000)
DRAM: 2048 MiB
Trying to boot from MMC2
NOTICE:  BL31: v2.4(release):v2.4
NOTICE:  BL31: Built : 11:03:17, Jan 18 2021
NOTICE:  BL31: Detected Allwinner H6 SoC (1728)
NOTICE:  BL31: Found U-Boot DTB at 0xc087388, model: Pine H64
NOTICE:  PSCI: System suspend is unavailable


U-Boot 2021.01 (Jan 18 2021 - 11:23:42 +0000) Allwinner Technology

CPU:   Allwinner H6 (SUN50I)
Model: Pine H64
DRAM:  2 GiB
MMC:   mmc@4020000: 0, mmc@4022000: 1
Loading Environment from FAT... Unable to use mmc 1:1... In:    serial@5000000
Out:   serial@5000000
Err:   serial@5000000
Net:   phy interface7
eth0: ethernet@5020000
starting USB...
Bus usb@5101000: USB EHCI 1.00
Bus usb@5101400: USB OHCI 1.0
Bus usb@5311000: USB EHCI 1.00
Bus usb@5311400: USB OHCI 1.0
scanning bus usb@5101000 for devices... 1 USB Device(s) found
scanning bus usb@5101400 for devices... 1 USB Device(s) found
scanning bus usb@5311000 for devices... 1 USB Device(s) found
scanning bus usb@5311400 for devices... 1 USB Device(s) found
       scanning usb for storage devices... 0 Storage Device(s) found
Hit any key to stop autoboot:  2  1  0
switch to partitions #0, OK
mmc1(part 0) is current device
Scanning mmc 1:1...
Found /extlinux/extlinux.conf
Retrieving file: /extlinux/extlinux.conf
191 bytes read in 2 ms (92.8 KiB/s)
Ignoring unknown command: MENULABEL
Ignoring unknown command: KERNEL
Ignoring unknown command: INITRD
Ignoring unknown command: DEVICETREEDIR
Ignoring unknown command: APPEND
1:    debian
No kernel given, skipping debian
SCRIPT FAILED: continuing...
libfdt fdt_check_header(): FDT_ERR_BADMAGIC
78MMC: no card present
Scanning disk mmc@4020000.blk...
Disk mmc@4020000.blk not ready
Scanning disk mmc@4022000.blk...
** Unrecognized filesystem type **
Found 4 disks
No EFI system partition
BootOrder not defined
EFI boot manager: Cannot load any image
MMC: no card present

Device 0: unknown device
ethernet@5020000 Waiting for PHY auto negotiation to complete........ done
BOOTP broadcast 1
DHCP client bound to address 192.168.1.218 (7 ms)
Using ethernet@5020000 device
TFTP from server 192.168.1.160; our IP address is 192.168.1.218
Filename '/extlinux/extlinux.conf'.
Load address: 0x42000000
Loading: *T T T T T T T T T T
Retry count exceeded; starting again
missing environment variable: pxeuuid
Retrieving file: /extlinux/pxelinux.cfg/01-02-07-36-ae-78-6c
Using ethernet@5020000 device
TFTP from server 192.168.1.160; our IP address is 192.168.1.218
Filename '/extlinux/pxelinux.cfg/01-02-07-36-ae-78-6c'.
Load address: 0x4fd00000
Loading: *T T T T T T T T T T
Retry count exceeded; starting again
Retrieving file: /extlinux/pxelinux.cfg/C0A801DA
Using ethernet@5020000 device
TFTP from server 192.168.1.160; our IP address is 192.168.1.218
Filename '/extlinux/pxelinux.cfg/C0A801DA'.
Load address: 0x4fd00000
Loading: *