“skaos” mentioned in the Rockbox forum that the markings on the e200 v2 SanDisk chip is very similar to the ones on the newer m200 models (as compared to the older m200 models which use different ones – at least marked completely different). It seems to imply that the m200 series have v2 models too.

But more interestingly, I downloaded the latest v4 firmware for the m200 series and looked at it with hexdump -C. While the file is encrypted or at least scrambled somehow (update: I was wrong the file is unencrypted, contains ARM code and strings), it features one plain text string at index 0x420:

AS3525_2_0.cr_5_0_develop.00020021010305000500

AS3525 is the name of a SoC from AMS (makers of the AS3514 “Stereo Audio Codec with System Power Management” chip used in the Sansa e200 series as well as in the Sansa c200 series) so to me it seems a bit too much of a match to be a mere coincidence! Oh, looking for UTF16-encoded strings, there’s one present that takes away all doubts: “AS3525/27 Demo Player“.

We’ll see what more we can dig up to really verify this theory. Fortunately, we managed to get docs for the AS3514 when some Rockbox guys visited the AMS HQ in Austria so hopefully we can get some for this thing too.

Now we have yet another firmware file format to figure out! ;-(

The SanDisk branded chip in the Sansa Clip does look very similar as well. If anyone has a firmware file for this target I’d be happy to check it out!