The module has no flash or eeprom on it, the bootloader must reside on external media. For this module that is either a SD card, or a serial EEPROM on the I2C bus. The wandboard carrier does not have the EEPROM, nor am I planning on having one on mine. The processor cannot do a raw boot off a USB memory stick, but it is possible to have the bootloader on the SD card do the rest of the loading from a USB stick, but of course that means the bootloader on the SD card has to be working.
There IS a way to boot off USB, plug the OTG port (with the proper cable) into a host port on a computer and run the right software on that computer to push a program into memory of the CPU, which could then download an image onto an SD card. I have read that some people have this working, but it's not a very mainstream technique because you need the right program on the computer (you have to deal with computer type, OS, all that fun stuff). In this mode the external program is basically using the ARM processor as a programmer for it's on board memory (SD card). I have to say that having the whole thing on an SD card is SO much better than the other approaches. I have worked with many an embedded system that had flash on the board, these things can be nightmares. I had one system that would completely erase the flash if power was turned off during a certain part of the boot process. Lots of other issues like this have been fairly common on these systems. Having it all on a removeable media is just much easier. That does not mean that you have to change out the SD card for installing upgrades etc. As long as the system is working you can do upgrades over Ethernet or USB. How that works is going to be software dependent. The only time you really need to replace the SD card is if you manage to completely trash it. John S. ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=97881 _______________________________________________ discuss mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/discuss
