fossil
Regular Contributor
The fact that you are not seeing sda1 because your usb is never mounted properly.Running those strings and rebooting produces no change because my routers mounts are ALWAYS sda first (NEVER sda1) .. Now the fact there is a protocol for this and I never have an sda1 whatever I do leads me to at least suspect I am not doing this right.
When you plug in the usb, create partition table with mklabel, format it "mkfs.ext4" and disable the "metadata_csum". Reboot router (if needed) your usb will be automatically mounted to "/mnt/sda1/"
Mount location is just a dir (/mnt/sda1/), you can even manually create a mount location (dir) of your choice and mount usb to that dir using mount cmd.