[RFC u-boot] booting from USB requiring mPCIe to USB adapter

With u-boot providing usbboot why is the mPCIe to USB adapter required, as per online doc

The second way is using the adapter (MPCIE1U-NO1) from mini PCIe to USB 2.0, which has to be plugged to the left mini PCIe slot, where is the SIM card slot

, which occupies another mPCI slot and the investment in said adapter, as opposed to be booting just from a USB device that is connected to one of the USB ports?

Too bad there is has not been any response because booting from an USB drive attached to one of the router’s exterior USB ports works with no issue.

and would have saved me from wasting funds on

Had three USB drives attached to the router (one via interior mPCIe adapter and two on the exterior ports) at boot time.

Perhaps the online doc stipulation is owed to the boot env setting root=sdX where the X could vary with multiple USB drives attached. However, u-boot provides for a more specific designation with root=PARTUUID= and thus does not get mixed up.

The caveat is that schnapps provides with ROOT_DEV only the sdX designation and one need to be aware of such when utilizing schnapps on such USB drive.

Well, being on TOS5.x and after a few updates booting from USB drives connected on the exterior USB ports is not working any-more. Now u-boot does not find/discover any USB drive connected on the exterior USB ports, it only finds USB drives connected via the interior adapter.

A bit strange, one days it works just peachy and next day not.