Today developer Yifanlu has released a new plugin named USBMC. USBMC allows one to mount a USB device at boot time and with Enso this means it will work all the time. Check out the release notes and the download link provided below.
Release Notes:
This is VitaShell's patches for USB storage support as a standalone plugin. If loaded on startup (before SceShell), it will automatically mount the USB storage as ux0 instead of the memory card or internal memory.
Release Notes:
To install, copy the plugin to ur0:tai/usbmc.skprx and add that path to the taiHEN ur0:tai/config.txt under *KERNEL. If you have a memory card inserted or you have a Vita with internal memory (LCD and PSTV), you must deleteux0:tai/config.txt from the original memory and use ur0:tai/config.txtfrom now on. This is because taiHEN loads before the memory card redirection patches and will attempt to read config.txt from there first.
Full credits to The_FloW for these patches