Network copy-nand

Introduction

This is a recipe for using copy-nand over the network, so you can replace your OS image without having to copy stuff onto a USB key. I have tested it only with Q2C18 firmware, but it probably works with a few other older versions.

It has some limitations:

1. It doesn't use the .CRC file to check the data (this is because of a deficiency in the firmware HTTP implementation that doesn't let you have two streams open at the same time; that could be worked around at some point by changing copy-nand to pre-read the CRC file into a buffer).

1. It isn't as fast as doing copy-nand from a USB key, but it probably compares favorably to the total process of downloading first to the key, then copying from the key to NAND.

Assumptions

• You are using the wireless LAN. A wired USB Ethernet interface probably works too (omit the "wifi" line), but hasn't been tested.
• There is a DHCP server on the network to which you are connected
• You know the IP address of an HTTP server with the nand image file. It might be possible to use a DNS name instead of an IP address, but for some reason OFW DNS lookup wasn't working the last time I tried it at the OLPC offices in Cambridge.

Procedure

 wifi media lab 802.11
 patch noop ?open-crcs copy-nand
 copy-nand http:\\209.132.176.61\images\nand505.img

Discussion

The "wifi" line above sets the SSID of the access point. That line isn't necessary if you are using a wired network interface. The default SSID is "OLPCOFW", so if you are setting up a special wireless network for firmware testing, you can use that SSID name to save some typing.

The "patch" line disables CRC checking, as a workaround for a problem described in the introduction section.

The URL in the copy-nand line must use backslashes instead of forward slashes. Long URLs like the following will also work, if you can manage to type the whole thing without making a mistake.

 http:\\209.132.176.61\olpc\streams\development\LATEST\devel_jffs2\olpc-redhat-stream-development-devel_jffs2.img

Disclaimer

This is a quick hack procedure provided in the hope that it might be useful, but is not currently supported officially (because I have too many other critical-path issues). If you should choose to file any trac tickets against it, expect to have them reassigned back to you.