On 03/12/2016 02:08 PM, John Crispin wrote: > > > On 11/03/2016 15:28, Matthias Schiffer wrote: >> On 03/11/2016 02:46 PM, Joseph Marlin wrote: >>> We certainly haven't. I've tried applying these patches - >>> http://thread.gmane.org/gmane.comp.embedded.openwrt.devel/39001 >>> >>> to no avail. I still get hit by a "Error code 2 - Firmware Check Failed". >>> >>> I'm really suspecting this comes down to an intentional check by Ubiquiti >>> to prevent us from flashing, as described on this list and in this comment >>> on the ticket - https://dev.openwrt.org/ticket/20982#comment:16 >>> >>> I have not yet had a chance to change the image header and CRC to look like >>> a Ubiquiti image, nor do I know how to offhand, but I hope to give it a >>> shot soon. >> >> Hi, >> there is a lot of misinformation about this issue going around, in >> particular, the wiki is plain wrong (I'll fix that some time soon.) >> >> Here's what's going on: >> >> * OpenWrt had wrong partition sizes in its UBNT AirMax firmware for a long >> time >> * Old AirOS and the corresponding U-boot version had a bug that made U-boot >> ignore the partition sizes defined in the firmware image. This made OpenWrt >> work with the old U-boot despite its broken partition sizes >> * The new AirOS has been fixed in this regard (but contains a new bug). >> This also means that the broken OpenWrt images don't work anymore and can >> cause even more breakage >> * The new U-boot/AirOS did *not* change the flash layout. Both AirOS 5.5.x >> and 5.6.x use the same flash layout, the changed flash layout reported in >> the wiki is caused by broken OpenWrt images! >> * The OpenWrt trunk since r48829 and the CC branch since r48849 are fixed, >> meaning they define the correct partition sizes >> * The "Newly-erased block contained word ..." messages are a consequence of >> a missing patch in CC that has been backported as r48849 (the new U-boot >> doesn't remove flash protection, so the flash is just read-only from >> OpenWrt; TFTP recovery is the only way to upgrade in this state) >> * AFAIR "Error code 2 - Firmware Check Failed" is the consequence of a bug >> in the new U-boot: after flashing an image with broken (smaller) partition >> sizes, the recovery doesn't accept images with the original partition sizes >> anymore >> >> Getting out of this state is not easy: you have a U-boot on your device >> that doesn't accept correct images, and an OpenWrt version that doesn't >> allow writing to the flash. >> >> Through a serial console, you can try fixing the settings in U-boot; when I >> tried this the last time, I wasn't able to do so, but maybe I did something >> wrong. The U-boot console has a few interesting settings (I forgot the >> exact commands, but the "help" command should tell you everything you need >> to know): >> >> * You can reset the MTD layout to the defaults. This makes the recovery >> accept correct images again. Unfortunately, in my experiments, this setting >> was not permanent even when I saves the environment after resetting the >> layout. In the hindsight, I remember there being a setting to disable flash >> protection, maybe that would made have the environment saving effective. >> >> In the end, I fixed this by creating a patched OpenWrt image that allowed >> me to write to the uboot and uboot-env partitions; this allowed me to write >> back backups I had made of the uboot and uboot-env before I broke the flash >> layout by flashing OpenWrt. Obviously, this does not work if you don't have >> backups... >> >> * If you don't plan to ever go back to AirOS again, it might be okay to >> just ignore the broken MTD layout in the U-boot settings. Get into the >> U-boot console, reset the MTD layout, start recovery, and flash an OpenWrt >> version after trunk r48829 or CC r48849. >> >> >> I hope this helps. I'd be interested if you find a way to parmanently reset >> the MTD layout from the U-boot console; unfortunately, I don't have a test >> device available at the moment. >> >> Regards, >> Matthias >> > > Hi Matthias > > looking at a US and EU image i see only 1 bit changed in the header. and > reading what you wrote above it sound like a small change to our image > generation process will make EU unit flashable again ? if so do we have > a patch or could you tell me which unit to order on amazon.de that has > the latest uboot with this bug fix so i can fix the regression in trunk. > sound like a lot of trouble and all caused by a small regression that is > easy to fix or did i miss something here ? > > John
I don't known anything about the differences between the EU and US versions, but I expect that my analysis is valid for both. AFAICT, OpenWrt did define the XM layout incorrectly from the beginning (~2009), this was fixed by my patch series 2 weeks ago (r48828 - r48830). As OpenWrt is fixed now, the trunk snapshots should just work. In CC, these have been backported as r48846 - r48848 (and r48849, which is also necessary so OpenWrt works with the new U-boot version), so 15.05.1 will also contain the fix, whenever it is released. The problem is that flashing the broken images on devices with the new U-boot will break the MTD layout in a way that U-boot's TFTP recovery will not accept the fixed images after that. I don't know of a way to fix this without a serial console (and even with one, this is not trivial.) I could try creating a "fix image" that can be flashed through recovery even without a console and fixes the MTD layout... Matthias
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