GP32 Reading From The Firmware Chip

[chris]

Two questions:

1) If I were to store data in the firmware, after the end of all the executable code, could there be any unpleasant side effects?

2) Assuming the answer to (1) is no, is there a relatively easy way of getting at it, i.e. seeking to a particular offset and reading in the data? By relatively easy, I mean I don't understand assembly, interrupts and whatnot.

Anyone able to help?

 

[Squidge]

If you use a portion of flash not used for anything else, there will be no strange effects because of it. However, remember this is flash - not ram, so you'll need to erase before writing - so you can't use it if you plan on updating the area often.

I'd recommend storing the data on the SMC unless it's small enough orpossibly in the E2 (but only if it needs to be global and/or you don't want SMC routines in your program)

 

[chris]

If you use a portion of flash not used for anything else, there will be no strange effects because of it.

Excellent, I suspected as much

However, remember this is flash - not ram, so you'll need to erase before writing - so you can't use it if you plan on updating the area often.

No I don't plan writing to to it at all (except for the initial flash)

Perhaps I should explain. I've recently been playing with the firmware tools mentioned in previous discussions. I've made my own firmware which loads YAFL or the EuroFW. But it displays this on startup (slightly censored):

And it goes MOOO! Which is obviously marvellous but I want to share my joy with the world. So I thought it would be great if I could find a way for yr average GP32 user to have their own startup screen and sound effect. I don't want to store this on the SMC as I want this displayed regardless of what SMC is inserted or even if there is no SMC inserted. It would be quite easy to knock up a tool for inserting this data into the unused space in fw.bin before flashing.

But how would you read it?

 

[woogal]

Why let people change it? whats wrong with a cow going Mooooooooooo!
The company I work for was originally called Moocow Digital Media. We've been bought out and gone through several name changes since then, but we still use Moocow as a department name

 

[chris]

Well, of course there's nothing at all wrong with a mooing cow. Cows are my second favourite animals (cats are best, despite the hundreds I've annoyed through GpKat). They look so peaceful and they taste so good! (cows not cats) And they squirt milk!

But I'm sure people would want the address details changed at the very least.

EDIT: Wheeee! I've figured it out. I'll start on it now.

 

[ColinR]

Now this is an EXCELLENT idea. You'd need somebody who knows a thing or two about the GP32 to take the stolen GP32 back to it's factory default state, and that's unlikely to be your regular opportunist thief. It won't stop the GP from being stolen in the first place, but may improve it's chances of reappearing in future (slightly).