diff --git a/board/sbc8641d/README b/board/sbc8641d/README index a051466..af18088 100644 --- a/board/sbc8641d/README +++ b/board/sbc8641d/README @@ -26,3 +26,24 @@ and settings may change with board revisions. -------------------- PCI: The PCI command may hang if no boards are present in either slot. + +4. Reflashing U-Boot +-------------------- +The board has two independent flash devices which can be used for dual +booting, or for u-boot backup and recovery. A two pin jumper on the +three pin JP10 determines which device is attached to /CS0 line. + +Assuming one device has a functional u-boot, and the other device has +a recently installed non-functional image, to perform a recovery from +that non-functional image goes essentially as follows: + +a) power down the board and jumper JP10 to select the functional image. +b) power on the board and let it get to u-boot prompt. +c) while on, using static precautions, move JP10 back to the failed image. +d) use "md fff00000" to confirm you are looking at the failed image +e) turn off write protect with "prot off all" +f) get new image, i.e. "tftp 200000 /somepath/u-boot.bin" +g) erase failed image: "erase FFF00000 FFF3FFFF" +h) copy in new image: "cp.b 200000 FFF00000 40000" +i) ensure new image is written: "md fff00000" +k) power cycle the board and confirm new image works.