USB host mode has been somewhat of a slog, which continues.

USB host mode lets you plug in random USB devices to your N900 using just a commonly available F-F adaptor cable plugged into the normal nokia USB cable.

Current status.

At first, we were informed back in september by nokia that 'OTG' can never work - which some took to mean no host mode.

This through much investigation, aided by MohammedAG, Docscrutiniser, myself, and many others, as well as much reading of schematics turned out to be strictly true.

A standards compliant 'OTG' mode can never work properly, the hardware is not connected in the right way to make it possible.
However, the 'OTG' controller in the n900 can also be forced through poorly documented commands into a more 'normal' USB host mode, similar to most PCs. (though with limitations)

However.

A couple of months ago I posted 'USB HOST - coming soon'.

At that time it seemed likely to be true.

Rapid progress was being made in numbers of areas, and the task remaining wasn't quite clear.

Pages and posts were written with that in mind, so look a bit optimistic now.

At the moment, things have stalled, due to the fundamental problem that to do it right - a reliable USB hostmode without screwing around plugging it into a PC - seems to involve a bit of relatively complex kernel hacking.

And none of those involved in the project has the skills and/or time.

So, it's stalled.
Efforts are now being made to publish the current state of the effort, and what needs to be done, to encourage more developers.

If, and only if you are able to actively help with kernel development, or have an understanding of the Mentor Graphics USB host architecture, come and join us over on freenode over on #maemo-hostmode-discussion .

Otherwise, feel free to discuss it here.

Please note - we understand many people are waiting for USB host, and that there are many, many cool things that can be done. We don't need to hear this, as we completely understand and agree.

In general at this time, most reports of stuff working are _not_ reliable.

They at best work for some people, for some devices, at some times, and are not reliable.

This is largely due to the interaction of:

* Poorly understood hardware (the main datasheets involved are 3000 pages, several revisions, each of which mention the USB hardware in passing, often in frustratingly little detail in some aspects)
* Poorly understood software - the kernel drivers are fragmentary and incomplete, with lots of bugs that interfere with implementing hostmode properly.
* Poorly understood closed binaries - The nokia bootloader and BME do odd and not completely understood things to the USB hardware, that make the initial state unclear, and also reset the hardware at various inconvenient times.
* Hardware bugs. There are several issues with the Mentor Graphics USB host integrated onto the CPU, and the way it's used in the n900. It seems that all of these can be worked around.

Progress is continuing, but slowly. Over the next couple of days, some of us in the project are going to be working on documenting the current state, so that it's easier for people fresh to it to get involved.

Thanks!, and sorry for the earlier optimism.