nRf9151 Development Kit (nRF9151DK) connection to laptop does not result in character device file creation (no /dev/ttyACM* ).

Question

Hello nordic team! 
 Issue: 
 I am reaching out because one of my nRF9151DK does not seem to have associated character device files created when I plug it into my laptop, and thus I am not able to target it to flash application code. I do not think there is an issue with my laptop or associated kernel drivers, as my other nRF9151DK seems to work fine, and upon plugging into my machine, results in two character devices (/dev/ttyACM0 and /dev/ttyACM1) being created which I can use to flash binaries and serial print logs. 
 
 Troubleshooting / What I've done 
 Looking at my dmesg logs below, it appears that my kernel 'cdc_acm' driver does not recognize the 'not-working' devkit, but recognize and create the associated character device files for the 'working' devkit. 
 Not working devkit dmesg log: 
 [ 555.740952] usb 1-1.4.2: new full-speed USB device number 16 using xhci_hcd
[ 555.844023] usb 1-1.4.2: New USB device found, idVendor=1366, idProduct=0101, bcdDevice= 1.00
[ 555.844040] usb 1-1.4.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 555.844047] usb 1-1.4.2: Product: J-Link
[ 555.844052] usb 1-1.4.2: Manufacturer: SEGGER
[ 555.844057] usb 1-1.4.2: SerialNumber: xxxxxxxxxxxxx 
 Working devkit dmesg log: 
 [ 649.949527] usb 1-1.4.2: new full-speed USB device number 17 using xhci_hcd
[ 650.052185] usb 1-1.4.2: New USB device found, idVendor=1366, idProduct=1059, bcdDevice= 1.00
[ 650.052202] usb 1-1.4.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 650.052208] usb 1-1.4.2: Product: J-Link
[ 650.052213] usb 1-1.4.2: Manufacturer: SEGGER
[ 650.052218] usb 1-1.4.2: SerialNumber: xxxxxxxxxxxxx
[ 650.084752] cdc_acm 1-1.4.2:1.0: ttyACM0: USB ACM device
[ 650.086108] cdc_acm 1-1.4.2:1.2: ttyACM1: USB ACM device
[ 650.088693] usb-storage 1-1.4.2:1.5: USB Mass Storage device detected
[ 650.089609] scsi host3: usb-storage 1-1.4.2:1.5
[ 650.091694] hid-generic 0003:1366:1059.000A: hiddev1,hidraw7: USB HID v1.00 Device [SEGGER J-Link] on usb-0000:00:14.0-1.4.2/input6
[ 651.141165] scsi 3:0:0:0: Direct-Access SEGGER MSD Volume 1.00 PQ: 0 ANSI: 4
[ 651.141946] sd 3:0:0:0: Attached scsi generic sg0 type 0
[ 651.145083] sd 3:0:0:0: [sda] 21829 512-byte logical blocks: (11.2 MB/10.7 MiB)
[ 651.146009] sd 3:0:0:0: [sda] Write Protect is off
[ 651.146021] sd 3:0:0:0: [sda] Mode Sense: 0b 00 00 08
[ 651.146669] sd 3:0:0:0: [sda] No Caching mode page found
[ 651.146681] sd 3:0:0:0: [sda] Assuming drive cache: write through
[ 651.174603] sda:
[ 651.174676] sd 3:0:0:0: [sda] Attached SCSI removable disk 
 
 I also noticed that the 'not-working' devkit appears to the 'lsusb' command as a 'SEGGER J-Link PLUS' device, while the 'working' devkit appears just as a 'SEGGER J-Link' device. 
 
 I have also tried to press and hold the RESET button on the devkit with no results - but I assume that only resets the application core or nRF9151 itself, not the OB debugger chip. 
 
 Possible solutions? 
 I was wondering if someone could share with me the recommended way to go about 're-flashing' the nRF9151DK with the factory firmware for it, so I may check and see if this resolves my issue, or if perhaps something is corrupt in the underlying hardware or with the OB Debugger itself, and thus it would not be worth trying to resolve. 
 I am skeptical that it would be an issue with my host laptop, as one of the devkits seems to work fine (both devkits were shipped as a pair together). 
 
 Devlopment Setup: 
 Both devkits are : nRF9151DK - HW v 0.9.0 
 Host laptop OS: Ubuntu 24.04.1