Inside the SDS7012 Oscilloscope: Disassembling the Bootloader
If you have an OWON SDS7012 or are simply intrigued by o’scope hacking, you’ll want to check out this blog post (and others) by Christer Weinigel. For reference the user manual for the S3C2416 processor at the heart of the device can be found online here [PDF].
The main processor in the SDS7102 is a Samsung S3C2416 System On a Chip (Soc) with a DDR SDRAM as main memory and a NAND flash for storage. A basic embedded system very similar to the Samsung SMDK2416 reference design.
I’ve worked with other SoCs in the S3C24xx family before, so I kind of knew what to expect from the bootloader. NAND flash is a bit unreliable in a way, it’s normal for it to develop bit errors over time and that some flash pages are so damaged that they can’t be used at all. Any decent NAND flash file system will have to support error correcting codes (ECC) to fix bit errors and have mechanisms to remap bad flash pages. Most NAND manufacturers guarantee that the first sector or three in flash will not develop any errors, and thus it’s possible to put a minimal first stage bootloader there.
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