On Sun, 2012-03-11 at 16:29 -0500, Jonathan Nieder wrote: > Ben Hutchings wrote[1]: > > > My understanding is that in general we cannot assume that uboot is > > upgradable at all, because: > > > > 1. Linux may not have access to the flash partition containing it. On the dreamplug I have: $ cat /proc/mtd dev: size erasesize name mtd0: 00080000 00001000 "u-boot" mtd1: 00010000 00001000 "u-boot env" Although I must confess that I've only ever updated u-boot via the u-boot command line (not for any particular reason, just the method I first discovered). I don't know about other kirkwood platforms, although I can see some relevant MTD partition declarations for GuruPlug and SheevaPlug and a handful of other boards under the relevant arch/arm/mach-kirkwood/foo-setup.c. > > 2. The factory-installed uboot may have board-specific setup code which > > is not included in mainline uboot. I've been using the Debian supplied u-boot on my DreamPlug basically since I got it. One unfortunate wrinkle with the factory supplied image is that it reuses the GuruPlug machine id instead of defining a new one. This has the potential to make thing a bit tricky and is the reason I switched to the Debian supplied u-boot ASAP. Fortunately the upstream Dreamplug support is now being implemented via DT so I suppose this is not going to be an issue in practice. > > 3. A power failure during an upgrade may be unrecoverable without > > specialist hardware. The specialist hardware in this case is the JTAG dongle which is £27 if bought with the dreamplug or £32 if bought separately later. The same dongle also exposes the serial UART (both that and the JTAG appear as USB devices) so I think it wouldn't be so unusual for folks to have one nor all that onerous to require it. Although I suppose £27 is rather large compared to the £139 cost of the dreamplug itself. FWIW the required software (openocd) is present in Debian. A fact for which I am very grateful since I've "bricked" my Dreamplug more than once ;-) > > Do we know that none of these apply to the Kirkwood platform? If not, > > the kernel must retain compatibility with older versions of uboot. I don't know how relevant this is but so far there has been no kernel with DreamPlug support in Debian itself, patches are only just going into mainline now. Ian. > > Cc-ing submitters, Ian, Michael, and Prafulla in case they have hints. > Thanks to all for your work on this so far. [1] has context. > > Thanks, > Jonathan > > [1] http://bugs.debian.org/658759 > > > -- Ian Campbell Government [is] an illusion the governed should not encourage. -- John Updike, "Couples"
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