• https://www.chromium.org/chromium-os/developer-information-for-chrome-os-devices/samsung-arm-chromebook

I have two chromebooks, one is working and one is bricked

Samsung ARM Chromebook (working)

localhost ~ # cat /proc/cpuinfo 
processor       : 0
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 48.00
Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt 
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xc0f
CPU revision    : 4

processor       : 1
model name      : ARMv7 Processor rev 4 (v7l)
BogoMIPS        : 48.00
Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt 
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xc0f
CPU revision    : 4

Hardware        : SAMSUNG EXYNOS5 (Flattened Device Tree)
Revision        : 0000
Serial          : 0000000000000000


localhost ~ # flashrom --flash-name
flashrom v0.9.4  : 244249c : Dec 09 2016 03:49:59 UTC on Linux 3.8.11 (armv7l)
flashrom v0.9.4  : 244249c : Dec 09 2016 03:49:59 UTC on Linux 3.8.11 (armv7l)
vendor="Winbond" name="W25Q32DW"

localhost ~ # flashrom --get-size
4194304

localhost ~ # flashrom --wp-status
WP: status: 0x00b8
WP: status.srp0: 1
WP: status.srp1: 0
WP: write protect is enabled.
WP: write protect range: start=0x00000000, len=0x00200000

localhost Downloads # flashrom -r chromebook-spi.rom 
Block protection could not be disabled!
Reading flash... SUCCESS

bricked, recovery doesn't help

This chromebook reports that it wants to do recovery, but inserting (few different) usb sticks generated using http://www.google.com/chromeos/recovery instructions doesn't help

https://dl.google.com/dl/edgedl/chromeos/recovery/linux_recovery.sh

arch

https://wiki.archlinux.org/index.php/Samsung_Chromebook_(ARM)

setenv bootargs root=/dev/mmcblk1p2 rootfstype=jfs rootwait rw
mmc dev 1
ext2load mmc 1:1 42000000 vmlinux.uimg
bootm 42000000

custom firmware

• https://www.chromium.org/chromium-os/developer-information-for-chrome-os-devices/custom-firmware
• http://selinuxproject.org/~jmorris/lss2013_slides/safford_chromebook_takeown.pdf
• https://www.chromium.org/chromium-os/firmware-porting-guide/using-nv-u-boot-on-the-samsung-arm-chromebook

dpavlin@nuc:/nuc/books/Chromebook$ wget http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow.kpart.bz2
--2017-01-19 19:05:28--  http://commondatastorage.googleapis.com/chromeos-localmirror/distfiles/nv_uboot-snow.kpart.bz2
Resolving commondatastorage.googleapis.com (commondatastorage.googleapis.com)... 216.58.206.16, 2a00:1450:4001:820::2010
Connecting to commondatastorage.googleapis.com (commondatastorage.googleapis.com)|216.58.206.16|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 281844 (275K) [application/octet-stream]
Saving to: ‘nv_uboot-snow.kpart.bz2’

nv_uboot-snow.kpart.bz2       100%[================================================>] 275.24K  1.37MB/s    in 0.2s    

2017-01-19 19:05:28 (1.37 MB/s) - ‘nv_uboot-snow.kpart.bz2’ saved [281844/281844]

• https://blogs.s-osg.org/use-mainline-u-boot-non-signed-kernels-exynos-chromebooks/

flash using raspberry pi

unplug battery before attempting this! rpi3 can power flash memory

# backup

root@rpi3:/home/pi/flashrom-0.9.9# ./flashrom -p linux_spi:dev=/dev/spidev0.0 -r chromeboot-bricked.rom
flashrom v0.9.9-r1955 on Linux 4.4.27-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Calibrating delay loop... OK.
Found GigaDevice flash chip "GD25LQ32" (4096 kB, SPI) on linux_spi.
Unsetting lock bit(s) failed.
Reading flash... done.

# flash version from another chromebook

root@rpi3:/home/pi# time ./flashrom-0.9.9/flashrom -p linux_spi:dev=/dev/spidev0.0 -w chromebook-spi.rom 
flashrom v0.9.9-r1955 on Linux 4.4.27-v7+ (armv7l)
flashrom is free software, get the source code at https://flashrom.org

Calibrating delay loop... OK.
Found GigaDevice flash chip "GD25LQ32" (4096 kB, SPI) on linux_spi.
Unsetting lock bit(s) failed.
Reading old flash chip contents... done.
Erasing and writing flash chip... FAILED at 0x00002000! Expected=0xff, Found=0x14, failed byte count from 0x00002000-0x00002fff: 0xfbb
ERASE FAILED!
Reading current flash chip contents... done. Looking for another erase function.
FAILED at 0x00000000! Expected=0xff, Found=0xa3, failed byte count from 0x00000000-0x00007fff: 0x7d35
ERASE FAILED!
Reading current flash chip contents... done. Looking for another erase function.
FAILED at 0x00000000! Expected=0xff, Found=0xa3, failed byte count from 0x00000000-0x0000ffff: 0xfac8
ERASE FAILED!
Reading current flash chip contents... done. Looking for another erase function.
FAILED at 0x00000000! Expected=0xff, Found=0xa3, failed byte count from 0x00000000-0x003fffff: 0x3dea4f
ERASE FAILED!
Reading current flash chip contents... done. Looking for another erase function.