As for saving the network setup, there isn't really any standard in Linux from the command line.  Well, there sort of is, in that cnetworkmanager drives NetworkManager which drives wpa_supplicant which associates with the network.  For a number of reasons, chumby has chosen to directly communicate with wpa_supplicant.

When you boot, a script called start_network reads the file /psp/network_config, and configures the network.  Here, for example, is my network_config (passwords and all!):

 <configuration allocation="dhcp" key="duplification" encoding="ascii"
                encryption="WPA2" auth="WPAPSK" hwaddr="00:22:55:F2:FA:A1"
                ssid="Semisucculent" type="wlan" />                               

Valid encodings are "ascii" or "hex".  They determine what form the key is in.  If you really want to specify your 128-bit PSK, you can set this to "hex"

Valid allocations are "dhcp" and "static".

If you set allocation to "static", you'll need to add keys for ip, netmask, gateway, nameserver1, and nameserver2.

Encryption should be WPA, WPA2, WEP, or NONE.  I think WPA and WPA2 are interchangeable in our current setup.

Auth should be WPAPSK, WPA2PSK, WPAEAP, WPA2EAP, WEPAUTO, or OPEN.

If you set auth to WPAEAP or WPA2EAP, add a key "username" with your EAP username.  Set the "key" to your EAP password.

hwaddr is ignored.

Type can be wlan, lan, or for the adventurous, 3G.

As for the slowness of the C compiler -- The memory bus is 131 MHz.  That's about as fast as an early Pentium, but without the out-of-order execution.  And it has 64 megs of RAM.  Poor little thing, trying to run a modern compiler.  I've seem g++ eat up all 64-megabytes of RAM just compiling a single file!  If you compile with all optimizations turned off, that might speed it up.  Aside from that, I've got nothing.

Depending on the image, you may need to fix the partition table (basically use fdisk to delete and recreate the first partition fixing the size).  I wrote up something on Ladyada's wiki.  Also, do a "dmesg" - sometimes filesystem errors will force it read-only even if you mount it differently but if there is something causing it there will usually be something in the kernel message log, and just doing e2fsck -f on the unmounted partition might help.  I've not had similar problems.  Also make sure you are on the right filesystem since symlinks can jump between them.

The standard root image is in another post on this forum.  You can use dd to copy it to any SD, but it has the bad partition.

http://forum.chumby.com/viewtopic.php?pid=31177#p31177

So you can always go back to a working copy.

My notes are at:

http://wiki.ladyada.net/chumbyhackerboard/microsd

The chumby hackerboard I received had the 6 partitions on the uSD out of the boc, complete with the overlap problem, only /mnt/storage (and its containing partition) was stretched to the 1Gb.  I think it has 2 roots to insure it can boot if one gets broken.  They also may have other differences.