#185: Need better SPI FLASH recovery procedure -------------------------------+-------------------------------------------- Reporter: [EMAIL PROTECTED] | Owner: [EMAIL PROTECTED] Type: task | Status: new Priority: high | Milestone: BTest-1 Component: linuxbios | Keywords: -------------------------------+-------------------------------------------- If you brick a B-test board by writing bad data to the SPI FLASH, the recovery procedure is painful, involving figuring out how to boot DOS, then running a DOS program that takes a long time (the Quanta HW engineer says from 15 minutes to an hour). A better approach would be useful.
I think I know how to do it faster, without using DOS. I now have a Forth program that talks the EC serial recovery protocol. I'm currently running it on another OLPC board, but it can also be booted on a PC from a LiveCD or USB key. I have verified it by reading out the SPI FLASH contents on an A-test board. I am pretty sure that the DOS program does extra work that can be avoided. With the procedure that is documented in the EC recovery spec, it takes 10+ minutes to read out the entire 1 MiB FLASH. But I can do it in 2/3 that time by avoiding some unnecessary steps, and I get the same data back. Thus I think the time can be cut down to about 7 minutes. But with the Open Firmware payload, only half of the FLASH is used, so the time would be just over 3 minutes. And if we wanted to go even faster, we could make a custom payload that just has the reflash code plus a serial downloader. That would get it down to about a minute, plus the time it takes for the serial downloader to do the rest (about half a minute). If we needed to, we could go even faster. The serial line speed limitation is not in the EC, but rather in the host PC, whose baud rate tops out at 115200. I have a couple of little tester boxes that I build in my previous job that can run a serial line at 500K. They run Forth, so the code I have written so far would "just work" on them. -- Ticket URL: <http://dev.laptop.org/ticket/185> One Laptop Per Child <http://laptop.org/> _______________________________________________ Devel mailing list Devel@laptop.org http://mailman.laptop.org/mailman/listinfo/devel