Lab Notes – Hacking file_storage.c

Progress Update

I made attempt 3 to use file_storage.c as a means of presenting an ISO image on the Pre as a CD-ROM drive over USB.  I tried grabbing several of the more recent versions of file_storage.c from git.kernel.org in an attempt to back-port them to the 2.6.24 kernel.

I found the following:

Stories of Warning for HP (Palm)

A warning for those who enter

 

What are the consequences of a device whose mass storage driver is down-revved?  What dangers loom on the horizon for those that ignore these dangers?  It is these questions that I seek to answer through the use of two extremely realistic and likely scenarios.

Using the Palm Pre as Xbox 360 Storage (the finale)

The joy of discovery!

15 days ago, I set out to determine why I couldn’t use my Palm Pre on my Xbox 360.  We all start somewhere, but I started with absolutely no knowledge of the composite gadget framework or Palm’s rockhopper composite driver.  In retrospect, I spent a lot of time asking silly questions and researching irrelevant things.  But once again I have been awarded for persistence, while picking up some great knowledge and tools for the future.

For the last 2 days, I have relished the joy of discovery.  Truth be told, this problem was solved 2 years ago by one Felipe Balbi on the linux-usb mailing list.  The next logical question is why the problem exists on so many devices if it was fixed 2 years ago?  Am I really the first person to discover this problem and solution and actually care enough to try and get it fixed on Palm and Android devices?

Read on as I reveal all that I know. (Palm users can skip to the good stuff by grabbing the latest UberKernel release and plugging in to their Xbox 360)

Using the Palm Pre as Xbox 360 Storage (part 2)

In my last post, I incorrectly theorized that the reason my Xbox 360 could not see my Palm Pre was because the mass storage driver was implemented as BOT instead of CBI.  BOT or Bulk Only Transfer has only 2 endpoints, bulk-in & bulk-out.  CBI or Control Bulk Interrupt has 3 endpoints, bulk-in, bulk-out and interrupt.

After spending some time in the code, I finished my cosmetic CBI driver hack, essentially making the Pre look identical to my working USB thumb drive in every single way.  This was not the solution!  I now have a working solution and it happens to be BOT, so we can safely say that the CBI vs BOT theory is moot.

Lab notes below.