ConnectCore 6UL showing gibberish on serial console and won't bootup

I was testing my bitbacked installation of Digi embedded Yocto.
After a week running and a hard reset the console was just showing gibberish and won’t bootup. See image1.
Following the process to recover:
I was able to get into the system with the simple “boot” command in Uboot without the console showing the described behavior. See Output1. But when removing the BOOT-jumper and starting the device normally, the gibberish comes back and the device won’t start!

EDIT: It has nothing to do with the BOOT-jumper and the boot command. Only when the micro USB cable is plug in/ unplugged it is working / not working.

Can someone help with that or at least explain what is happening?

Image1: from 2020-04-21 11-17-51.png?dl=0

U-Boot dub-2017.03-r4.1+g98d7b2a (Sep 27 2019 - 22:18:02 +0000)

CPU: Freescale i.MX6UL rev1.1 528 MHz (running at 396 MHz)
CPU: Industrial temperature grade (-40C to 105C) at 44C
Reset cause: POR
I2C: ready
DRAM: 256 MiB
PMIC: PFUZE3000 DEV_ID=0x30 REV_ID=0x11
NAND: 256 MiB
In: serial
Out: serial
Err: serial
Model: Digi International ConnectCore 6UL SBC.
ConnectCore 6UL SOM variant 0x02: Industrial Ultralite 528MHz, 256MB NAND, 256Mh
Board: ConnectCore 6UL SBC Pro, version 4, ID 135
Boot device: USB
Boot from USB for mfgtools
Empty manufacturing boot command ‘bootcmd_mfg’
=> boot
ubi0: attaching mtd1
ubi0: scanning is finished
ubi0: attached mtd1 (name “mtd=3”, size 12 MiB)
ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 bytes
ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048
ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
ubi0: good PEBs: 96, bad PEBs: 0, corrupted PEBs: 0
ubi0: user volume: 1, internal volumes: 1, max. volumes count: 128
ubi0: max/mean erase counter: 33/26, WL threshold: 4096, image sequence number:0
ubi0: available PEBs: 0, total reserved PEBs: 96, PEBs reserved for bad PEB han4
Loading file ‘boot.scr’ to addr 0x80800000…

Executing script at 80800000

Skipping mounting already mounted ubifs fs
Loading file ‘zImage-ccimx6ulsbc.bin’ to addr 0x80800000…
Skipping mounting already mounted ubifs fs
Loading file ‘imx6ul-ccimx6ulsbc-id135.dtb’ to addr 0x83000000…
Kernel image @ 0x80800000 [ 0x000000 - 0x5c5a70 ]

… Normal starting behavior

did you actually program a new U-boot to flash after booting via recovery procedure? This is described in “Update U-Boot in the NAND” art of the same page you have referenced. IT appears that your u-boot is corrupt and has to be reflashed.

Sorry for being unclear.
Yes I did “Update U-Boot in the NAND” as well but it did not help.

What I have found out just now is that when removing the micro USB cable it is showing the gibberish stuff again. It is only working with the micro USB cable plugged in; it has nothing to do with the BOOT jumper.
See edit.

If you believe your board is defective, please open a new support case by sending email to
Please provide your company name and the Serial number of the SBC.

Okay thanks a lot.

okay just to let you know:
I had to reset U-Boot with

env default -a

This let me boot without micro-USB Cabel pluged into the computer.
But since then I can’t access the Console… but well, so far so good.

if you believe your board is faulty please open a support case and request an RMA