===== What is this about? =====
Some notes on the FiiO M3K Mini HiFi.  As of July 2021, the M3k is available from amazon.com . A build of [[https://www.rockbox.org|rockbox]] for the device exists, and works just great!

===== Links =====
{{ :hardwarerelated:mp3player:20200215_145256_m3k_x1920.jpg?300|M3k w/ rockbox}}
  * [[https://www.rockbox.org/wiki/ConsoleEmulators|rockbox emulators]]
  * [[https://www.amazon.co.jp/dp/B07GPPC7BS/|M3k on Amazon Japan]]
  * [[https://www.fiio.com/m3k|details from vendor]]
  * [[https://blog.fluxcoil.net/posts/2021/08/rockbox-badapple-m3k/|My blog entry on the "Bad apple" port to the M3K]], [[https://github.com/christianhorn/badapple-lua|the code]], [[https://forums.rockbox.org/index.php/topic,53945.0.html|Rockbox forum]]

===== Why rockbox? =====
  * OpenSource pieces
  * support for many codecs, like ogg vorbis, Amiga mod and sid files
  * _really_ configurable: multiple bookmarks per file can be set, fading from one file into the next and much more
  * There are plugins for playing doom, quake, duke3d
  * [[https://download.rockbox.org/daily/manual/rockbox-sansafuzeplus/rockbox-buildch12.html#x14-34900012.4.15|A One-Time password client]]
  * emulation
    * gameboy/gameboy color emulator are buildin:place files with .gb or .gbc extension
    * [[https://forums.rockbox.org/index.php?topic=51219.0|NES emulation project exists]]
  * If you need something, you can create it!

==== Rockbox current notes ====
This is the native port, recommended nowadays.
  * [[https://www.rockbox.org/wiki/FiioM3K|link to the port]]
  * [[https://forums.rockbox.org/index.php/topic,53858.0.html|Install instructions]], echoing here:
    * fetch jztool and bootloader.m3k
    * create a vfat filesystem on the card, copy bootloader.m3k to the card, unzip a rockbox release to the card (.rockbox directory)
    * Turn off the M3K, keep volume-down pressed while connecting to the Linux system, screen stays dark but lights at the touch fields light up
    * ./jztool fiiom3k load bootloader.m3k
    * Take a backup of the current bootloader, install the new one.  From now on, the menu can be reached by holing volume-up while powering on the M3K.
    * Fetch a daily build for the FiiO M3K from [[https://www.rockbox.org/daily.shtml|here]], unzip it into the root-directory of your microsd-card. It creates a .rockbox directory. Careful, there seem to be also "bad builds", so by chance you hit one of these. For example, 2021-10-19 does not boot for me.
    * Just start up the M3K, it will boot Rockbox from the directory.
  * The fast forward/rewind issues from the non-native port are gone.

==== Rockbox 1.4.3 notes (old, deprecated) ====
This was the first "port", rockbox more running in userspace as alternative to the native firmware. On each start, one has to select "rockbox". The native port is recommended nowadays.

  * [[https://forums.rockbox.org/index.php/topic,52952.0.html|forum link with details]]
  * [[https://xvtx.ru/rockbox/download.htm|rockbox 1.4.3 firmware for the M3k]] 
  * [[https://www.fiio.com/newsinfo/82055.html|update instructions]]
  * **usage notes for rockbox 1.4.3 on M3k**
    * fast forward/rewind do not work in the default config, just a 'flickering' is seen. To fix this, go into "Playback Settings > Fast Forward / Rewind > FF/RW Accel" and change it to 'Very fast', then long pressing to fastforward/rewind works.
    * press the on/off button for 2 seconds to lock the device, and again to unlock it
    * creating bookmarks:
      * ensure these settings are in place
        * Menu->Settings->General->Bookmarks->On Stop->Yes
        * Menu->Settings->General->Bookmarks->Load Last->Ask
        * Menu->Settings->General->Bookmarks->Recent->Unique Only
      * Then, to create a bookmark, press the 'select' button for 2 seconds, that's the lowest button on the left side.

==== Rockbox buildenv ====
  * https://www.rockbox.org/wiki/FiioM3K
  * https://www.rockbox.org/wiki/HowtoWritePlugins
  * https://www.rockbox.org/wiki/DevelopmentGuide
  * https://www.rockbox.org/wiki/CrossCompiler
<code>
# Fedora34
sudo dnf install gmp-devel git
git clone git://git.rockbox.org/rockbox
cd rockbox/tools

# This should now build the crosscompiler for us
vi rockboxdev.sh
### I customized the path, to not build into /usr/local
./rockboxdev.sh

# At this point I needed to customize the PATH to point at the compiler:
export PATH="/home/chris/Downloads/rockbox/rockboxbin/bin:$PATH"

# Do a build
mkdir build
cd build
../tools/configure
make -j
make zip
# This should leave a zipfile which we can deploy as .rockbox
# to the sdcard and start the M3K!
cd ..

# Do a build of the simulator
mkdir buildsim
cd buildsim
../tools/configure
make -j
make fullinstall
./rockboxui
</code>

==== Bad apple@M3K ====
  * https://blog.fluxcoil.net/posts/2021/08/rockbox-badapple-m3k/ -- article
  * https://github.com/christianhorn/badapple-lua -- repo
  * https://github.com/TT-392/Pinetime-bad-apple-video-processor -- a Bad apple @pinetime project