USB Host Mode

External vbus power is easy:

Connect your type A (with ID-pin shorted) microUSB to USB cable into webOS. Plug the data leg of USB-Y cable (usually found with 2.5" external HDD enclosures and such) into this cable. Plug the root of the Y cable into a hub or whatever device you plan to use. Plug the "power" leg of the Y cable into some powered usb socket be it a powered hub, a PC or whatever. Enjoy your usb device.

Example of cable that will work: http://www.ebay.com/itm/High-Quality-micro-USB-USB-Female-Cable-USB-OTG-N900-/170687828639?pt=PDA_Accessories&hash=item27bdc9929f Search for OTG cable on eBay and thee are plenty.

The USB-ID should be 1-1

Internal VBUS:

TBD.

If you get a error like this in dmesg:

This command got me past this error:

This worked for me and hopefully it can be of use to someone