Thinking Small

Apparently the Zipit folks have obsoleted the original built-in app on the Zipit Z2.  This means the jffs on the internal 8MB flash contains about 5.5MB of useless applications and data.  Worse yet, it's supposedly possible to get the stock app stuck in some sort of infinite loop of update requests if it's never been connected to Zipit wireless for an initial firmware update.  Now I've never experienced this myself, but I also haven't booted a new Zipit into the stock app for quite a while now.  If you're really worried about it you should probably bypass IZ2S and run the latest FlashStock to replace the firmware with uboot and the spiffy rescue image.  Then you can run one of the many uboot userlands like z2lite.

However uboot is significantly slower to boot than the stock bootloader, and all of the uboot userlands seem to require reformatting your SD card to ext2, which may significantly shorten the lifespan of the SD.  So I got to thinking, maybe I should consider replacing the stock app on the internal jffs.  Now, what could I fit into 5.5MB?  A minimal Rockbox installation would be sweet.  I could also go for a minimal gmu install to turn the Zipit into a dedicated internet radio device requiring no SD card.  But both of these apps are just a wee bit bloated for the 5.5MB available on the internal flash.  So how do I make them fit? We could use an IZ2S version of UPX to cut the executables and libs down to about one third the size.  Then things just might fit.

The UPX source compiled without a hitch and seemed to work just fine on the IZ2S rockbox executable.  Supposedly the source version of UPX has somewhat lower performance than the pre-built UPX executables, but sometimes you just have to take what you can get.  It's probably good enough for my purposes.  Now I just need to sacrifice the stock app on one of my Zipits and then see what fits.  Meanwhile, here's the UPX executable for IZ2S.

upx-iz2s.zip