UPDATE: Upgrading to SNAPSHOT, r8021-9e58c20 solved the problem
Earlier today, I had Barrier Breaker installed on my AP121U, and I had USB storage working with no problems. I then upgraded to 18.06. Everything seemed to go well, and all the other functions of the Access Point are working as expected, but I lost the ability to use my USB storage.
I am using the exact same USB flash disk (formatted with vfat) that I was using before in Barrier Breaker.
Here are the USB drivers installed:
# opkg list-installed | grep usb
kmod-usb-core - 4.9.120-1
kmod-usb-ehci - 4.9.120-1
kmod-usb-storage - 4.9.120-1
kmod-usb-storage-uas - 4.9.120-1
kmod-usb-uhci - 4.9.120-1
kmod-usb2 - 4.9.120-1
kmod-usb3 - 4.9.120-1
libusb-1.0 - 1.0.22-1
usbutils - 007-7
Here are the file system modules installed:
# opkg list-installed | grep fs
e2fsprogs - 1.44.1-1
fstools - 2018-04-16-e2436836-1
kmod-fs-hfs - 4.9.120-1
kmod-fs-msdos - 4.9.120-1
kmod-fs-ntfs - 4.9.120-1
kmod-fs-vfat - 4.9.120-1
libext2fs - 1.44.1-1
When I lsusb, I can only see the root hub, not the Mass Storage device (previously, I could see the Mass Storage device under the hub).
# lsusb -t
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-platform/1p, 480M
Here are the dmesg messages including usb:
# dmesg | grep usb
[ 4.580938] usbcore: registered new interface driver usbfs
[ 4.585099] usbcore: registered new interface driver hub
[ 4.590493] usbcore: registered new device driver usb
[ 9.547768] usbcore: registered new interface driver usb-storage
[ 9.560986] usbcore: registered new interface driver uas
And I cannot see any devices starting with sd:
# ls -l /dev/sd*
ls: /dev/sd*: No such file or directory