Wow! Really nice mod. Is hacking the NAND driver a trivial matter (asking because from what I hear, Sharp did not release source files). Is hacking the driver the only thing that needs to be done to have the Zaurus see and use the new NAND storage as ROM? Would love to see a screenshot of System Properties showing all that internal memory.
The nand driver is included in the sharp source tree (or in the cacko source tree, for that matter).
Hacking the driver shouldn't be too difficult, I hope to find the time to do that the coming weekend.
The hacked driver would expose the NAND as just another mtd partition, which can then be formatted using JFFS2.
Using a FS not specifically designed for flash would also be possible, but a big "don't do that" since ther is no wear-leveling.
Unfortunately JFFS2 does not perform well with big filesystem sizes, maybe I'll try YAFFS instead.
If you pre-tin the new memory chip leads, would that extend them enough to make soldering less risky?
Maybe.
I think applying flux to the old chip leads may also help a lot.
Interesting tidbits:
dd if=/dev/mtdblock of=/dev/null clocks in at about 2MB/s (on the 64MB flash)
This corresponds nicely to a benchmark I did on the PIO reads from the CPLD, however if I use the pxa dma engine I can read at >10MB/s.
Hooking up the chip-enable to the green led is just a temporary measure, I'm thinking of hooking it up using a transistor, with the base connected to CE0 using a resistor,
the emitter connected to CE1 an the collector connected to CE (while also leaving the pull-up in place).
This should act so that a low-level on CE1 gets only passed on to CE if CE0 is high-level and so works around the 'Sharp Kernel turns on/off both CE0 and CE1'.