I've been working for a few weeks now on the Samsung YP-S3 and thought it might be a good idea to start a 'New ports' thread about it.
I already started a wiki page about it, see
http://www.rockbox.org/twiki/bin/view/Main/SamsungYPS3The current status is that it is possible to run a rockbox bootloader in RAM. This bootloader contains simple demonstrations of stuff that already works, like display, backlight, LEDs, key input, radio, volume control, etc. It is not yet possible to access the file system in the NAND flash memory, so the bootloader does not actually boot anything.
We can run things in RAM thanks to a special DFU (device firmware upgrade) mode that allows you to send an executable over USB to RAM and start it. The code for all of this is already in the SVN repository with the exception of the linker file (boot.lds), so you can check this out if you want. This linker file determines which part of the code goes where (DRAM, IRAM, flash) and all of these references should be modified to point to the DFU RAM.
The current biggest challenges are (in my opinion):
* access to the NAND flash in such a way that we can read from the filesystem of the original firmware. The OF uses the Whimory flash translation layer (FTL) to perform wear-levelling and to present the raw NAND flash as a simple 512-byte block device. Openiboot has code for read-only Whimory access, but at a first look it doesn't seem to be compatible to what the YP-S3 uses.
* some way to install the rockbox bootloader permanently on the player