More Small Thinking

Well, I managed to squeeze an extremely stripped down copy of IZ2S onto the jffs of a stock zipit, with rockbox, dropbearmulti, and the retawq web browser.  This means you can boot the zipit with no SD card and get on the internet in a pinch (kinda, sorta).  As you can see in this (somewhat blurry) picture of retawq browsing this very blog, with nothing in the miniSD slot.

But the main purpose is to be able to run rockbox from the jffs so you can swap SD cards with different music on them at runtime.

To make things fit I stripped and upxed all the executables.  The jffs does it's own compression, but upx compression is slightly better.  I also removed just about everything I could - fonts, languages, themes, plugins, libs.  You name it, it's gone.  There's about 800K left on the jffs if you find something missing that you just can't live without.  I made softlinks for the rockbox plugins directories, so you can play them off the SD card if you really want to.  Static linked executables from IZ2S can also run off the SD card, although if you want that, you should probably just boot into IZ2S itself.

One little gotcha trying to put this together was the IZ2S tar program.  I couldn't get it to *create* an archive.  Only untar seems to work.  So I had to relearn cpio to get test builds off the jffs with my softlilnks intact.  I haven't used cpio in like 30 years...

Anyhow, here's how to install.  Put iz2jffs.tar.bz2 on an IZ2S SD card and boot it up.  Then you want to delete just about everything on /mnt/ffs except the start.sh script, the wpa_supplicant directory with the wifi drivers, and the properties.txt file with your MAC address.  After that you can unzip the new stuff, power down the zipit, and boot it up without the SD card.

cd /mnt/ffs

rm Zcovery
rm Zipit2
rm *.xml
rm *.arl

tar -xjpvf /mnt/sd0/iz2jffs.tar.bz2

The SD card (with all your music) shows up in Rockbox as Files/share/sd0.

iz2jffs.tar.bz2

Update:  I've been fiddling with the busybox from iz2s enhanced because it has so many goodies.  It's almost 600K upxed, but it may be worth it since you can get 100K back by replacing the full sed and netcat utilities in /mnt/ffs/bin.  I've also compiled and upxed tinyirc (37K) and I'm still trying to decide if the upxed dialog utility is worth it for the wifi script at 150K.  Here's a zip with these if anyone else wants to play.

iz2jffs-extras.zip

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