permanently disabling radio on Sansa clip

[mayer]

I have read some of the port topic "SanDisk Sansa c200v2, m200v4, clipv1, clipv2, clip+, and fuzev2" and see people have come quite a way to know these players. However, I didn't have the time nor the knowledge to read through all 129 pages.

I would like to say what I know and what I need and maybe everybody will end up gaining.

But before I start I would like to suggest that with such long topics you would have somewhere a separate topic with all the discoveries so far, in short, which is constantly updated. Maybe you could place a link to that topic in the first post of your port topic. That way people can easily catch up on the progress so far. This would be ideal for people like me, but also for new developers who would like to join.

Okay, so here goes:

You have already noticed that part of the last letter of the name of the FW bin-file has an effect on what features it includes.
You know that H and G enable Greek and Hebrew and that G disables the radio.
M and N does the same for Arabic.

Now you might wonder who on earth would like to disable the radio?
The answer is that some groups of both Jews and Muslims have an ideological believe that the radio is negative since the presentator has the “power” to influence the listener with his “heathen” and “heretic” believes. (So you see that Jews and Muslims have more in common than just the believe that tiny Israel is theirs. ) That’s why exactly those two languages have the choice of FW with radio and without radio.

We have established a “charity” which helps people disabling their radios on their MP3 players. With the Sansa we simply download the FW from the Sandisk forums, change the last letter to G or M and update the Sansa with it.

Many people have this done for their children’s MP3 player. I know that many people out there will see this as domineering or controlling, but they see it as protecting, similar to trying to make sure that children stay away from drugs and other harmful things. This is not the forum to discuss approaches in education and I therefore trust that people here will accept others for who they are and with their believes.

The major “problem” is that teenagers, being teenagers, have discovered that it is possible to reset the Sansa. I have seen it being done with the ClipV2 and I don’t know if it works with other models, but what they do is following:

When holding down all the buttons (that’s the menu button, the middle button and the round button around it) together whilst the Sansa is turning on, it will bring up a menu similar to the one you see after a FW upgrade, but with the first entry being “debugging” (or something like that). When chosen the test-option appears in the menu, and the version is shown with a t at the end.

I do not know if this procedure only changes the letter at the end and hence the features, or whether the t(est)- FW is hard-coded in the player and this procedure calls it up. Fact is that once done, the version remains t even after rebooting until the FW is manually changed again.

So now the question is whether there is a way to disable this reset option?

I was thinking along the lines of going in recovery mode by shorting out the pads and making changes is the coding there (would love to get your instructions of how and what to change), but I was hoping there would be a way to achieve that without disassembling the entire thing.

I would appreciate any input on this matter.

Whilst at it I would appreciate ways of disabling video on MP4 players.

Thanks in advance in the name of all religious fanatics.

[gevaerts]

You know that unless you remove the radio chip, the radio will still be there, right? Are you sure that its mere presence isn't a problem?

[LambdaCalculus]

Whatever happened to, "If you don't like what the device features, don't buy it"?

[AlexP]

You would probably be better off asking on sansa forums, we only tend to get involved in the OF enough to work out how to run Rockbox.

You could of course install an edited version of Rockbox that disables dual boot and the radio (but it'd still be there, they would just need to install standard Rockbox)

[mayer]

You know that unless you remove the radio chip, the radio will still be there, right? Are you sure that its mere presence isn't a problem?

As long as it is permanently disabled it shouldn't be a problem.
Nevertheless, if you could provide a schema and point out where exactly the chip resides, this might be a posible answer to my question.

Whatever happened to, "If you don't like what the device features, don't buy it"?

The problem is that no device exists with the exact features we want, so why not buy the device which suits me best and modify it to our needs?

You would probably be better off asking on sansa forums, we only tend to get involved in the OF enough to work out how to run Rockbox.

You could of course install an edited version of Rockbox that disables dual boot and the radio (but it'd still be there, they would just need to install standard Rockbox)

As I am totally new to Rockbox, I would appreciate if you (or anybody else) could give me exact directions as to how to achieve this and what the implications would be.

[bertrik]

I don't know how the original firmware would respond if you completely disabled the fm tuner chip.

One thing you could do is to leave the tuner chip present, but prevent the fm audio from going to the main mixer chip. This makes it appear as if the tuner chip is still present (you can still tune to a station), but there is no audio coming out.

Have a look at the PCB scan of the clip(v1):
http://www.rockbox.org/wiki/pub/Main/SansaClip/clipv2-back.jpg
The tuner chip is the square chip marked 0219 between the volume up/down buttons. Also have a look at chapter 7 of the datasheet of the si4702 chip.

To the right of this chip are three capacitors (the small black things). I believe the top (LOUT signal) and middle (ROUT signale) capacitor carry the fm audio. Removing or destroying them should prevent the fm audio from the tuner to go to the audio mixer.