How to boot Sansa into Rockbox with USB connected

[jsiddall]

I understand the reason these things boot into original firmware when USB is connected.  The problem is the assumption seems to have been that USB is only used for downloading.  However, when it is used in a car and USB is only used for charging then the default behaviour is not right and it really mucks up car mode.

Is it possible to have it look at what is connected to the USB port before deciding which firmware to boot?  Can anyone share some pointers on how I can disable the auto boot into original firmware when USB is connected?

UPDATE: Although I am not a developer I had a look at the source anyway.  Can I do something simple like comment out this?:

#define USB_HANDLED_BY_OF

[FlynDice]

Does anyone actually make use of the mmu and i/dcache info on the ViewHW info debug page anymore?  I'm thinking of removing that and adding  some more voltage related info that will be more helpful for future use.


@jsiddall:

I don't know if this will completely solve your problem but you can charge while running rockbox by holding a button down when connecting the usb cable.  You didn't mention which player so I don't know if telling you that it's the select button for an e200v2 helps....
It would be in the manual though.

[jsiddall]

@FlynDice:

I have a Clip V1.  The problem with having to hold down a button when the thing boots is that it pretty much defeats the usefulness of car mode for me -- and that defeats one of the main reasons for using RockBox at all.  My goal is to have the thing totally hands-off.  Throw it in the glove box and forget about it.  When I stop the car it stops too.  When I start the car, it picks up where it left off.

According to the docs RockBox doesn't do the turning on when plugged in part, but because the design of the Clip automatically turns on the device when USB is connected I _almost_ have the perfect solution -- except for starting the OF when USB is plugged in.

[saratoga]

The problem with having to hold down a button when the thing boots is that it pretty much defeats the usefulness of car mode for me

Good news.  You can't hold down a button to boot rockbox when powering on from external power.  You will always get the OF.

According to the docs RockBox doesn't do the turning on when plugged in part, but because the design of the Clip automatically turns on the device when USB is connected I _almost_ have the perfect solution -- except for starting the OF when USB is plugged in.

You can edit mkamsboot to do this.  Be very careful if you decide to do so, any mistake there will brick your clip with no chance of recovery. 

[jsiddall]

The problem with having to hold down a button when the thing boots is that it pretty much defeats the usefulness of car mode for me

Good news.  You can't hold down a button to boot rockbox when powering on from external power.  You will always get the OF.

According to the docs RockBox doesn't do the turning on when plugged in part, but because the design of the Clip automatically turns on the device when USB is connected I _almost_ have the perfect solution -- except for starting the OF when USB is plugged in.

You can edit mkamsboot to do this.  Be very careful if you decide to do so, any mistake there will brick your clip with no chance of recovery. 

Thanks for the tips.  Despite the fact that this all sounds precarious I really do want car mode to work so I am willing to risk the bricking.

I am not a programmer though so this is all a bit daunting.  I had a look at the code in rbutil/mkamsboot/dualboot/dualboot.S and near as I can tell if I change row 89 from this:

#elif defined(SANSA_CLIP) || defined(SANSA_CLIPV2)

to this:

#elif defined(SANSA_CLIPV2)

...and recompiled mkamsboot I should get what I am looking for.  Can anyone who knows this stuff confirm my guess?

[llhell]

@jsiddall:

I have the exact same issue with car mode, been waiting for a solution ever since I got my fuze over a year ago.

did you manage to edit mkamsboot to load rockbox on boot with external power, instead of the OF?
I'll be extremely grateful if you could share it with me

[jsiddall]

Good news!  With the help of a bunch of smart people on IRC I managed to create a couple of patches to get car mode working on my Clip v1.  The changes I made would apply to any Sansa AMS so they should work for you too.  Keep in mind though that these changes have never been tested on anything but my Clip and they do have a real chance of killing your player.  Proceed at your own risk!

I am posting them to Flyspray if you want to try them.

[lazpete]

Good news!  With the help of a bunch of smart people on IRC I managed to create a couple of patches to get car mode working on my Clip v1.  The changes I made would apply to any Sansa AMS so they should work for you too.  Keep in mind though that these changes have never been tested on anything but my Clip and they do have a real chance of killing your player.  Proceed at your own risk!

I am posting them to Flyspray if you want to try them.

Is there any chanse that i could get a hold of theses patches, and in that case, will it work on the clip+?
regards

//Lasse

[iletunic]

Good news!  With the help of a bunch of smart people on IRC I managed to create a couple of patches to get car mode working on my Clip v1.  The changes I made would apply to any Sansa AMS so they should work for you too.  Keep in mind though that these changes have never been tested on anything but my Clip and they do have a real chance of killing your player.  Proceed at your own risk!

I am posting them to Flyspray if you want to try them.

Bump for the patches... Would love to test them on Clip+

[saratoga]

Good news!  With the help of a bunch of smart people on IRC I managed to create a couple of patches to get car mode working on my Clip v1.  The changes I made would apply to any Sansa AMS so they should work for you too.  Keep in mind though that these changes have never been tested on anything but my Clip and they do have a real chance of killing your player.  Proceed at your own risk!

I am posting them to Flyspray if you want to try them.

Bump for the patches... Would love to test them on Clip+

They've been in SVN for almost a year.  Check the commit logs if you want to look at them.

[lazpete]

Excuse my stupidness, but what is SVN? And where do I find it?

[yapper]

http://www.rockbox.org/wiki/UsingSVN

[lazpete]

thx a lot.

[saratoga]

Alternatively, you can use the web interface linked from our front page.  The mkamsboot is under /rbutil

[iletunic]

They've been in SVN for almost a year.  Check the commit logs if you want to look at them.

Thanks. I compiled mkamsboot from SVN, but Clip+ still boots to OF when USB is plugged in.

I then tried changing dualboot.S:

Line 177: from "bne boot_of" to "beq boot_of"

but that just made it always boot to OF (I was hoping it'd boot into rockbox when USB is plugged in).

Then I tried changing the other jump at line 313, but that also didn't work (ie. still always boots to OF).

Anybody has an idea why? Should I just remove the jumps? I'm worried it will always boot to rockbox then, and I'll be left without USB.

Thanks.