I am starting (for my very first time) a new port to a HipStreet 4Gb MP3 Player (HS-193-4GB-MX). I have taken it apart and found the datasheet for its MCU, the ATJ3315C (datasheet found at http://www.datasheet4u.com/datasheet/A/T/J/ATJ331x-Actions.pdf.html
). I also know that it uses the PF368 AL 1524 for it's 4GB of flash memory (however I cannot seem to find a datasheet for this).
The datasheet says that it's instruction set is compatible with the Z80 (not quite sure what that is) but I have managed to find the instruction set for the Z80. I have assembly programming experience, so I am capable of programming.
However, I'm stuck. I simply don't know what to do or where to go next. I am trying to find the bootloader and use it to find where the operating system is located, so that I can overwrite that with linux or rockbox. How do I do this? Are there any programs that will take a snapshot of the entire memory map of the MCU, as well as the PF368's memory contents? And what about bricking it? I want to be able to reflash it to it's current, factory-default, state in the event of bricking.
Any advice would be greatly appreciated!