Rockbox Development > New Ports
Sandisk Sansa View
crackmonkey421:
You may need to sign before you encrypt instead of after; that's what I do, but it may work your way too. Maybe the "offs_id" needs set when you build. The firmware.mi4 for v1e200 rockbox gets accepted, so it must be similar to what you would do on an v1e200 to build an mi4 from a bin. I'll try some things when I get home.
Edit:
When you modified the original firmware.mi4, did you change the file size? Just wondering. I looked into it a little more and the commands look correct from what I've read. I'll try it to write and compile some custom code from scratch and build it in the same way.
Chronon:
I trimmed some off-topic posts. Please read the sticky and post in this thread only if you're contributing to the effort to port Rockbox to the Sansa View.
obo:
--- Quote from: crackmonkey421 on March 17, 2009, 03:42:11 PM ---You may need to sign before you encrypt instead of after; that's what I do, but it may work your way too. Maybe the "offs_id" needs set when you build. The firmware.mi4 for v1e200 rockbox gets accepted, so it must be similar to what you would do on an v1e200 to build an mi4 from a bin. I'll try some things when I get home.
Edit:
When you modified the original firmware.mi4, did you change the file size? Just wondering. I looked into it a little more and the commands look correct from what I've read. I'll try it to write and compile some custom code from scratch and build it in the same way.
--- End quote ---
With the OF:
the order in which I sign and encrypt doesn't seem to matter, both worked. Stripping the OF (mi4code decrypt -s), and building it again results in a larger file, but it still loads.
--- Quote from: j8048188 on March 17, 2009, 03:38:24 PM ---was the new checksum calculated correctly and inserted into the file?
--- End quote ---
There is a checksum, but I'm not sure if it's correct or not (since it's a CRC with a custom initial polynomial.. I've haven't yet checked this). But since the modified OF worked, I'd have to presume that the MI4 header is being setup in a way that the device accepts...
Edit: The OF uses 01030100 at 0x4 (default mi4code build option), and 0xEC at 0x2E4 (the default build offs_id).
crackmonkey421:
Yea, everything you've done looks correct as far as I've read. I got "Invalid Image" after it restarts with a very small block of custom code. I'm not sure what's causing this either. I would think someone with v1e200 experience (maybe even v1c200) might know because the v1e200 rockbox firmware is accepted and ran, so the v1e200 probably has similar issues that were accounted for in the rockbox firmware. One thought is to chop up the OF to figure out what parts are required to get it accepted and ran. Another idea is to take a closer look at the e200's mi4 source code to get ideas or even to build from.
obo:
Well, it works if I copy the file over in MSC rather than recovery mode - I guess the checks are stricter at that point, and required a patched bootloader?
The modified bootloader I used fails to write anything, so I guess the SD interface is different or at another location. I've found a few registers in the disassembly, but have yet to identify what any might be.
IRAM seems to be at 0x40000000 (normal PP), and I think it's 128K.
I2S init is at 0x70000000 (normal PP)
Other ones to look at are 0xc5000000, 0x7fc00000 and 0x80000000, but I'm sure there are more! This is proving to be quite a learning curve.
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