Presenting iPod as a standard USB mass storage device for in-car use?

[bifter]

Hi,

I've had a look through the forums so forgive me if I've missed any threads on this topic however I haven't found an answer.

I have a new car with a head unit that supports a USB connection to any device that can be presented as 'mass storage'. It works fine with the micro SDHC card in my HTC Hero, USB sticks and so on, however when I connect my iPod (4th gen greyscale) I get something like 'Device Error - Not Supported'.

'OK' I thought, 'I'll load Rockbox on my iPod and that will work!' However it doesn't. Whenever I connect the iPod I see a picture of a USB on the iPod screen and it displays 'Multimedia mode' and then reboots. I then get the error on the head unit and the iPod displays 'OK to disconnect'. I've tried fiddling with the HID settings in the menu but that hasn't helped. I also saw a suggestion to hold down the Menu button when the plugging the USB in but that doesn't work either.

Does anyone know if Rockbox can present the iPod as mass storage or, if not, any software that will? Cheers!

[gevaerts]

You're probably running a release build (3.5.1 if it's a recent install). Those have USB disabled because rockbox doesn't handle charging ipods from USB well at all. If you install a current build, it will use the rockbox USB implementation and not reboot, but you might have problems due to this charging issue.

[bifter]

Thanks for the prompt reply. I've tried installing the current build (r25423-100401) and you're right, it doesn't reboot. However the error message is still returned from the head unit. Any other ideas?

[gevaerts]

You could try disabling HID, but if that helps, I'd expect the Apple diskmode to also work.

One possibility I can think of is that the head unit matches the Apple USB ids. If that's the case, you could try with a custom rockbox build with different ids. You'd have to edit firmware/export/config/ipod4g.h in the rockbox source and change USB_VENDOR_ID and USB_PRODUCT_ID

[soap]

http://cleansoap.org/files/Rockbox-r25432_NonAppleVendor-ProductID.zip

I had the same thought (that the stupid head unit is balking at known iPods), so I'd be very interested in this trial.

Question, though, is your music still in the Apple firmware created directory structure or are you using a "more sane" directory structure?

IF this build doesn't do the trick AND if you are using the Apple created directory structure the next test would be to delete the Apple directories and test if that is what the head unit is looking for.

[bifter]

Looks like, if I want to exhaust the options, I'll have to invest a bit of time and effort! While I would count myself as IT literate I'm not a developer, I was just looking for a quick fix to the fact that my iPod won't play through the USB connection on the head unit.

If I want to amend the source, does this mean I need to install SVN?

Incidentally we're talking about the VAG head unit (VW/Skoda/Seat) and yes, I am using the Apple created directory structure - I am aware that, even if I can get it working, this will simply present a bunch of randomly named folders and files to the head unit but at least I would be able to play the files on shuffle and use the steering-wheel mounted controls to skip tracks. If I got it working I would probably reload my music collection anyway.

[soap]

I wasn't explicit before - but that link is to a custom build with the changes gevaerts was talking about.

[bifter]

Gotcha, cheers for that!

I was about to head off to bed anyway so will give this a try tomorrow. Am I able to just copy that folder structure over the top of the existing one or is there more to it? Sorry for noobness.

[soap]

Overwrite existing directory structure with new.

[bifter]

Well, the head unit must be checking the ID tags because that firmware you provided works like a charm!!! Many, many thanks! 

There will be a lot of happy people on the VAG forums when I tell them about this, except the ones that have forked out c.£60 for the manufacturer's cable - that uses the USB and the line in jack for some reason, plus cables all over the place!

Is this fix perhaps something that could be offered as an option in the settings for a future build? It's likely to be a common issue, more so now that USB connections are fairly standard in cars.

As for the charging thing, I'll keep an eye on that. The only slight worry when I was out and about earlier today was that my phone disconnected from the bluetooth, which it's never done before. It happened just the once and instantly reconnected but it seems a bit of a coincidence, presumably the head unit got a bit confused?

[saratoga]

Is this fix perhaps something that could be offered as an option in the settings for a future build? It's likely to be a common issue, more so now that USB connections are fairly standard in cars.

It sounds like a work around for a bug in your car's USB driver, so I don't think this would be considered for the main build.

[gevaerts]

Making USB ids user-configurable sounds like a really bad idea to me, so the only real solution would be to drop the ids used by the original firmware altogether, but that would involve buying a USB vendor id, and those are not cheap.

I'm afraid there is no real good solution for this unfortunately. We'll have to think about which downside is the most acceptable.

[Multiplex]

Incidentally we're talking about the VAG head unit (VW/Skoda/Seat)

Do you know the model number of that headunit? I'm wondering if this will work in my car...

[bifter]

Do you know the model number of that headunit?

Not off the top of my head but the car is a Seat Leon, 2010 build. I think the unit is common to a lot of the VW, Seat, Skoda range just with varying display modules on them. My thoughts are that this solution should work for most, if not all VAG head units that have USB - see below.

It sounds like a work around for a bug in your car's USB driver

Having thought about this I'm not so sure. I'm pretty sure that Seat offer iPod integration as an option - an iPod connector either in the glove box or under the driver's seat - though now that I look I can't see that option on their Web site!

Anyway I reckon they may be using the ID tags to try and stop people just mounting their iPods as mass storage, thus forcing them to buy the integrated option or buy after-market cables.

Making USB ids user-configurable sounds like a really bad idea to me

Not sure that I follow? Isn't there a generic mass storage option that could be toggled in the settings, like you can use an agent switcher in a browser for example? Alternatively use Cowon or iRiver or something, for the reasons above it may be the case that the head units are only looking for iPod IDs. Sorry for my ignorance if I'm misunderstanding.

[NiHaoMike]

Making USB ids user-configurable sounds like a really bad idea to me, so the only real solution would be to drop the ids used by the original firmware altogether, but that would involve buying a USB vendor id, and those are not cheap.

I'm afraid there is no real good solution for this unfortunately. We'll have to think about which downside is the most acceptable.

Is there anything wrong with using a generic mass storage ID?