I have a mercury mw151, the CPU is ar9331, 16M/64M a port 100 megabit network port, a USB/microUSB(Power), configuration as attached.
[[https://bugs.openwrt.org/index.php?getfile=1294]]
Since there is no corresponding firmware, I have been using the firmware of ts-d084, from BB until 19.07.8 version, and used quite well.
Recently I used the latest version 21.02.1 firmware and saw that FLASH is only recognized to 8M.
Also the device does not recognize the USB drive correctly after installing the corresponding USB driver.
opkg install block-mount
opkg install kmod-usb-core
opkg install kmod-usb-storage
opkg install kmod-usb-uhci
opkg install kmod-fs-vfat
opkg install kmod-usb2