SAMSUNG YH-920

[pyro_maniac]

@lowlight:
i PMed you some links found by nichlas. Could you have a look?

Are you going to commit your fm support patch soon? For me it worked on both YH-920 models.

[ThunderStorm]

If it worked for Nichlas on his yh-925, I can't think of why it wouldn't work on an 820.

Are the Janus versions seen as a USB mass storage device or MTP (you use Windows media player)? It needs to be a mass storage device to save the folder to the right place.

I placed it into my player when the player is recognized as a USB mass storage device. I pressed the forward button when I plugged it onto my computer. But I still don't know why it won't load the rockbox firmware(even if the bootloader works)

[Nichlas]

I don't know what difference this may do, but i found out the mi4key for the 925 Janus firmware.
I thought that it might be useful somehow in regards to getting the old OF to boot with the janus bootloader.
I used the dump ROM tool in debug and searched for a key in the file with mi4code.
Maybe its already been done?

Here is the key: 297961d2 ef77b629 2b401fd7 a58e486b

Link to decrypted janus firmware:

http://ul.to/ja8s9x

Merry Christmas

Edit:
I now have dual boot with the janus bootloader in flash and lowlights super bootloader on CF!
AND i got my radio back in OF!
This had nothing to do with the above, i just tried another old firmware file and i got the: database corrupt please connect and run repair util. Then i managed to find a copy of the the old firmwares systemfolder online.
And behold, it works!
Another nice thing is that i dont need to hit reset between OF and Rockbox, i think this is thanks to that the janus bootloader
is running in the background.

Thats all, good night!

[pyro_maniac]

I used the dump ROM tool in debug and searched for a key in the file with mi4code.

Which dump tool do you mean? You also have the jasnus bootloader file?

[Nichlas]

O sorry forgot to post the rom.
I used the dump rom content in the debugg menu to get to the janus bootloader.
I might be completley off, but the file generated worked to get the key for the firmware.

Here is a link to the rom file:
http://uploaded.to/file/hb0k8t

[pyro_maniac]

O sorry forgot to post the rom.
I used the dump rom content in the debugg menu to get to the janus bootloader.
I might be completley off, but the file generated worked to get the key for the firmware.

Here is a link to the rom file:
http://uploaded.to/file/hb0k8t

You talk about the OF debug menu? How did you get access to it?

EDIT: Hmm its a pitty but this bootloader looks only for "SYSTEM\F_YH925J.MI4" nothing else unlike the other ones.
Your dump looks like there are 2 bootloader in the file.

EDIT2: I was right. Your dump seem to include the bootloader and its backup. I attached a .tgz file.

[kugel.]

O sorry forgot to post the rom.
I used the dump rom content in the debugg menu to get to the janus bootloader.
I might be completley off, but the file generated worked to get the key for the firmware.

Here is a link to the rom file:
http://uploaded.to/file/hb0k8t

You talk about the OF debug menu? How did you get access to it?

EDIT: Hmm its a pitty but this bootloader looks only for "SYSTEM\F_YH925J.MI4" nothing else unlike the other ones.
Your dump looks like there are 2 bootloader in the file.

EDIT2: I was right. Your dump seem to include the bootloader and its backup. I attached a .tgz file.

He probably means the dump rom function in the Rockbox debug menu.

[pyro_maniac]

Ok, i hoped it was the OF debug menu.

[Nichlas]

Sorry to say that i did use the Rockbox debug menu, it had been usefull i imagine to uncover the OFs debug mode.

Anyway i hope the key and ROM dump can be of some use, i dont have the knowledge to analyze it, but i figure that the key at least can bed added to mi4code, and the minor version of it used in rockbox source. Then one could build a bootloader supporting the booting of the Janus firmware also (why one would want that i don't know) and maybe use triple booting, OF-Janus, OF and rockbox.
If a uniform format is required for rbutil, an instruction to update to Janus for all players could be used and thus making a rbutil with only one bootloader per samsung player?

Hope you all had a good Christmas.   

[AronVanAmmers]

I can confirm the bootloader from Lowlight (http://forums.rockbox.org/index.php?topic=6135.msg158824#msg158824) works on an YH-925GS with the MTP update. The bootloader should be called F_YH925J.mi4.

I've tried booting the different flavours of original firmware:

• Non-MTP firmware (http://www.samsung.com/download/FileView.aspx?cttfileid=246656&type=Digital+Audio+Player&typecode=8&subtype=Yepp&subtypecode=804&model=YH-925GS&filetype=FM&language=) can boot, but gives the error "database corrupt please connect and run repair util" like Nichlas had.
  • I tried to use the Samsung Recovery Tool (http://www.samsung.com/download/FileView.aspx?cttfileid=246636&type=Digital+Audio+Player&typecode=8&subtype=Yepp&subtypecode=804&model=YH-925GS&filetype=SW_cm&language=) to rebuild the library. The tool reports success, but after rebooting the error about corruption is still shown.
    
    Nichlas, any chance you could put the system folder for the original non-MTP firmware you found online up for download so I can try if booting the OF works for me?
• Janus MTP firmware (http://www.samsung.com/download/FileView.aspx?cttfileid=543891&type=Digital+Audio+Player&typecode=8&subtype=Yepp&subtypecode=804&model=YH-925GS&filetype=FM&language=) doesn't boot, Rockbox error messages: "Searching for key." "Can't load /System/OF.mi4"
• Decrypted MTP firmware from Nichlas (http://ul.to/ja8s9x) doesn't boot, Rockbox error message:  "Bad checksum"

Personally I'm only interested in the non-MTP OF, because it will re-enable the FM radio which was removed by the MTP upgrade.

Rockbox itself works very well. I didn't encounter any serious issues.

Thanks a lot for this from a new happy Rockbox user

Cheers,
Aron

[Nichlas]

Got this from AronVanAmmers, after he tried a copy of the system folder from OF:

"Cheers, the OF works! Finally I have my FM radio back. This device has become so much cooler today."

So one more has got their radio back on Janus firmware.

This new bootloader is great!

[AronVanAmmers]

Hi,

Indeed I'm a happy Samsung YH-925GS Rockbox user with restored FM radio functionality

Now that I've finished most of the Rockbox games (looove MazezaM and codebreaker , I've tried running Rockboy on the YH-925GS. I know Rockboy isn't core functionality and results vary, but I want to see what I can get it to do.

Running Rockbox r24117-091226.

Results (on simple greyscale games like Super Mario, Tetris and Prince of Persia):

- games are playable
- Keys work: up/down/left/right, rec=start, fwd=select, play=A, rev=B (or maybe the other way around)
- speed is about 50% of what it should be
- sound is distorted (it seems to play for about half a second, then silence, then play again, etc., with some ticks in between)
- can't reach the Rockboy menu, so can't try things like changing the palette or frameskip. I've tried the hold switch, combinations of keys and holding keys for a longer time.

Anyone tried this and got better results? How can I reach the Rockboy menu?

Cheers,

Aron

[richardash1981]

Is anyone still working on this? I've successfully got my S/H YH-925 running Rockbox following the wiki, but there are a couple of things which wouldn't harm for some attention:

* I can't get the original firmware boot to work, it always loads Rockbox. I'm a bit confused about boot loader vs main firmware, as I get the Samsung "Boot Loader" splash screen followed by Rockbox loading, and I'm not sure when to press left

* This player (a UK-bought YH-925 with Samsung on the case) definitely has an FM radio which works with the v2 firmware (this player has not been updated to Janus and I intend to keep it that way!), I haven't yet tested the patch to see if it can be got to work

* I suspect the backlight of never going out, which eats up the battery. I certainly can't see the screen getting brighter when I press the buttons

If internal voltage traces are needed have a 'scope and can take it apart to find out what the original firmware does (once I get it to boot it). Ditto if the contents of the original 925 SYSTEM directory (Build 2.13?) are useful I can post the tarball somewhere.

[saratoga]

Is anyone still working on this?

Since you're the first person to post in this thread in almost a year, probably not. 

[jimbo70]

I own a 820 with janus bootloader, and finally this night I've been booting rockbox !!!
to let it boot it I had to use the Iriver 20 Gb bootloader renamed as YH820_J.mi4
( http://download.rockbox.org/bootloader/iriver/H10_20GC.mi4 )
and now finally it worksss !

Dado, you're a damn genius!!! 
It works like a charm!!
I just registered to the forum to thank you for this simple solution!

ps
please developers, clean up the page dedicated to the YH 820 model, there are vague and conflicting instructions, just point them to Dado's workaround.