Hi, quick status update: I still didn't manage to prepare what I promised weeks ago, sorry about that. It's unclear when time will allow for it, but I'm not forgetting about it.
Le mardi 16 février 2016 à 16:55 +0100, Albin a écrit : > Den 2016-02-16 kl. 16:31, skrev Paul Kocialkowski: > > sorry for the late answer, > > > No worries! > > > Le mardi 19 janvier 2016 à 14:41 +0100, Albin a écrit : > > > > Either way, it's hard to find out exactly why it's refusing to boot > > > > externally, provided that Libreboot still shows the warning about > > > > external media booting being enabled. Still, it is probably either about > > > > the kernel you extracted not being in the right format or the partitions > > > > not being set up correctly. > > > > > > > > Perhaps you could send me the kernel file you extracted (I'm not sure I > > > > have a backup of mine) and I could prepare a known-to-work disk image > > > > for you to boot from. > > > That would be very nice but unfortunately I cannot access the files on > > > the USB drive where I saved it. When I insert it into my other (X86_64) > > > computer it shows up as an "unknown" device. Besides, external media > > > booting has now been switched off as well so I really need to reflash > > > the firmware. > > What I can do is prepare a "recovery" SPI flash image with external media > > boot > > explicitly enabled and signature verification disabled, as well as a disk > > image > > to dd into an sdcard/usb drive that contains a basic debian rootfs with the > > cros-specific tools (that I will soon integrate in Libreboot). > > That would be awesome! As I said above I don't think that I can send you > my ChromeOS kernel as I'm unable to access the file system on the USB > drive where I saved it. Would you still be able to pull it off? Of course! Once you have control over what's on the SPI flash, the rest is no longer problematic. > > I'll probably write up a blog post with instructions while I'm at it. > > Hopefully, > > I'll find time to do this in the next week. Feel free to remind me soon ;) > > > > > > > > > > > > > If that fails, it might mean that you'll have to relfash the SPI flash > > > > with an image that allows running unsigned kernels, which will give us > > > > more flexibility. > > > > > > > > Either way, your device is not lost and I'm confident there will always > > > > be a way to straighten it out. If you feel like you don't want to pull > > > > this off yourself, we could see about you sending me the device so that > > > > I do what's needed to fix it. > > > Thank you for the encouragement! I do have an SPI programmer and some > > > experience with flashing externally (T60 and macbook2,1) so I would like > > > to try to unbrick the c201 myself. Still, I could need some help with > > > how to connect the wires to the BBB. I'm familiar with most of the > > > abbreviations but I don't know how to connect HOLD#, CLK and CS#. Maybe > > > you, or somebody else, could expand the documentation with details about > > > BBB wiring, like it's in the other guides.That's very generic SPI flashing > > > stuff, so I don't think it belongs in the C201 > > guide in particular. CS# and CLK are signals to connect to the matching ends > > on > > the BB while HOLD# and WP# have to be pulled-up (you can connect them > > directly > > to VCC if you don't care about potential excessive current flowing). > > I don't understand what you mean about pulling up. I guess that write > protect isn't necessary since taking out the Screw should be enough, but > if HOLD# needs to be connected, then I don't know how. I think removing the screw is enough, the pull resistor is likely already on the board. It might be the same for HOLD#. If not, just connect a resistor from that pin to VCC (a few kOhm should do), or just connect the pin directly to VCC if you're feeling lazy. > > > Another thing that would be useful, I think, is a libreboot > > > configuration for veyron_speedy with some of the security features > > > switched off. That would give somebody who needs to recover their device > > > another option than reinstalling the backed up factory image. > > That would be doable by changing some GBB bits, so perhaps we could consider > > that. I was more thinking of a quick and dirty code-commenting approach, but > > if > > this can be done cleanly without changing the code too much, why not > > > > Perhaps recovery instructions could be part of the C201 install guide then. > > > > Thanks for your feedback! > Thank you! Cheers, -- Paul Kocialkowski, low-level free software developer on embedded devices Website: https://www.paulk.fr/ Coding blog: https://code.paulk.fr/ Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/
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