Rescued Kerlink Station (Bosch OEM) – stuck at login / firmware update not working

Hi everyone,
I recently rescued a Kerlink LoRaWAN station (Bosch-branded OEM version) from the trash.
I’m a tinkerer and wanted to bring it back to life as a learning project for LoRa / The Things Network.

I’ve already booted it into recovery mode and have serial debug console access.
I can reach the login prompt, but none of the default Kerlink passwords from the Wiki work.

On the network side, only port 22 (SSH) is open – it only accepts public key authentication, password login is disabled.

I also tried a firmware update using the latest Kerlink image.
I prepared a USB stick as described in the Wiki (FAT32, update files on the root), and when I plug it in, the device detects it but does not start the update automatically.

Here’s the relevant console output after inserting the USB stick:

Wirgrid_08060191 login:
[ 562.590000] usb 1-1.1: new full-speed USB device number 4 using usb-ohci
[ 562.730000] usb 1-1.1: New USB device found, idVendor=0930, idProduct=6545
[ 562.740000] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 562.750000] usb 1-1.1: Product: TransMemory
[ 562.750000] usb 1-1.1: Manufacturer: TOSHIBA
[ 562.760000] usb 1-1.1: SerialNumber: 5B860B000171
[ 562.780000] usb-storage 1-1.1:1.0: USB Mass Storage device detected…
[ 565.900000] sd 3:0:0:0: [sda] Attached SCSI removable disk

And part of the boot log (recovery mode):

rmaV2 kickstart svn1607 (Dec 3 2014 - 14:04:05)
CPU 266MHz
NAND: Micron On-Die ECC
U-Boot 2009.03-svn1610 (Sep 03 2015 - 11:08:31)
Product: WirmaV2 lora V4
Autoboot in 1 seconds, enter Password:

My questions:
:right_arrow: Is this device still usable at all without Bosch OEM credentials?
:right_arrow: Is there a way to flash a generic Kerlink image or reset the login?

Would be a shame to let working hardware go to waste.

Best regards,
Max

Please slow down on the inline text formatting - it really distracts from just reading the info.