Sunday, December 12, 2010

A stripped-down Rockbox build for the Archos V2 Recorder

The Archos V2 Recorder has only two megabytes of RAM. This RAM is used for the software running on the device, and whatever RAM remains may be used as a buffer to store MP3 data. It's a very small amount of RAM and even at 128 kbps, most songs cannot fit. Because of this, the hard drive has to spin up frequently to read additional data.

In 2007 I noticed how newer versions of Rockbox left less free buffer space and I decided to make my own build with more free space. The first step was a RomBox build. This helped a lot, but I wasn't satisfied. I saved more RAM by disabling various features which I didn't need: code page loading, language loading and the voice interface. With this build, I have 1.774 MB of buffer space.

I also fixed a few bugs, either by backporting fixes from later versions or by fixing the bug myself. Most notably, I fixed the charging screen issues.

Here are some files associated with this custom build:
This is all based on Rockbox from November 2007. I've used this build for years on my V2 Recorder without running into any significant problems. I view it as a finished product, because I see no need to update the V2 Recorder to newer versions of Rockbox, and my attempts to minimize memory usage encountered diminishing returns.

I did not make any builds for other old Archos devices because I don't have access to those devices for testing. It should not be hard to build for those. The only tricky part is what I did to the language system to save RAM.


This is based on Rockbox r15545. You can now download just the patch. Here's a list of the included fixes and changes:
  • FS#9638 - temp_cue is unused and wasting memory 
  • FS#7631 - Charging screen broken on V2 Recorder. Several fixes enable the charging screen, display of input current on the screen, and proper startup from the charging screen.
  • FS#9635 - Instant backlight turn-off on FM/V2 Recorder
  • FS#8163 - Rockbox (Sansa) hangs in settings menu. This fixes a crash caused by the scrolling title used for setting text horizontal scrolling speed. 
  • Removal of language changing, with English language strings used directly from ROM. (This requires manual intervention when building.)
  • Removal of voice functionality.
  • Removal of codepage changing
  • Removal of the database (this is part of the RomBox instructions).
  • Removal of low battery shutdown
  • Unused conditionals for removing bookmark functionality. This part is probably incomplete and bookmark functionality remains.
In general, the removals are kind of incomplete and messy. I removed the main memory using parts, but I didn't remove all traces of those features. For example, the settings for removed features still remain. I did not extensively test all possibilities, but I did not run into any problems whatsoever over years of use.

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