Mounting Coral Dev Kit EMMC as USB using U-boot

I am following the instructions from this answer: backing up and restoring the eMMC and also described here: https://developer.technexion.com/docs/using-u-boots-ums-command-to-write-flash-storage-over-usb-otg

I am able to run ums 0 mmc 0 and get the loading animation which I understand to mean the emmc can now be visible from the host. However I do not see any new device when I run fdisk -l or lsblk. I know the emmc is not empty because I can ssh into the operating system on it. Any ideas why the emmc is not showing up as a USB device?

Make sure you have 3 cables connected! The power one, the one next to it to your host machine (OTG data), and the USB-A to USB-micro-B cable (must be a USB data cable). In theory, you can connect to the serial console just with the first two. But connect all to be safe.

I had connected only the power and the USB-A to USB-micro-B one, and had the same problem. Once I connected the third one (next to power, the OTG), it changed the output and in my host machine (Linux), three folders opened, being able to see the contents of my board and sd card on it.

Before connecting the data OTG cable:

sudo fdisk -l
Disk /dev/sda: 111,8 GiB, 120034123776 bytes, 234441648 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 9ACCAF0B-CB4C-4BC2-841E-D9CC265BEB8C

Disposit.    Start    Final Sectores  Size Tipo
/dev/sda1       34    97656    97623 47,7M EFI System
/dev/sda2    97657  7070453  6972797  3,3G Microsoft basic data
/dev/sda3  7071744 80799743 73728000 35,2G Linux filesystem

After connecting the OTG cable (the process in which it was "stuck" was still running), no worries:

sudo fdisk -l
Disk /dev/sda: 111,8 GiB, 120034123776 bytes, 234441648 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 9ACCAF0B-CB4C-4BC2-841E-D9CC265BEB8C

Disposit.    Start    Final Sectores  Size Tipo
/dev/sda1       34    97656    97623 47,7M EFI System
/dev/sda2    97657  7070453  6972797  3,3G Microsoft basic data
/dev/sda3  7071744 80799743 73728000 35,2G Linux filesystem


Disk /dev/sdb: 7,3 GiB, 7818182656 bytes, 15269888 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 85B83F23-51C4-4403-8BAC-906FF5800F4E

Disposit.    Start    Final Sectores  Size Tipo
/dev/sdb1    16384   278527   262144  128M desconocido
/dev/sdb2   278528   280575     2048    1M desconocido
/dev/sdb3   294912  4489215  4194304    2G desconocido
/dev/sdb4  4489216 15253503 10764288  5,1G desconocido

And these folders should open up, also kind of a visual input that you did things right (apart from the fdisk -l):