Dobrica Pavlinušić's random unstructured stuff
Chromebook: Revision 42
Links
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"
https://media.digikey.com/pdf/Data%20Sheets/Winbond%20PDFs/W25Q32DW.pdf
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]
This might be upstream bios update, but u-boot doesn't start at beginning, so it's probably some update format and not raw image.
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.
file:///nuc/books/Chromebook/GD25LQ32_Rev1.3.pdf
I repeated this twice and checked md5sum of both files to verify that I have stable connection with programmer
# 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. No usable erase functions left. FAILED! Uh oh. Erase/write failed. Checking if anything has changed. Reading current flash chip contents... done. Good, writing to the flash chip apparently didn't do anything. Please check the connections (especially those to write protection pins) between the programmer and the flash chip. If you think the error is caused by flashrom please report this on IRC at chat.freenode.net (channel #flashrom) or mail flashrom@flashrom.org, thanks! real 14m40.938s user 0m1.600s sys 0m9.000s # hm?! root@rpi3:/home/pi# time ./flashrom-0.9.9/flashrom -p linux_spi:dev=/dev/spidev0.0 -r chromebook-broken.rom.3 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. real 1m19.653s user 0m1.140s sys 0m0.700s root@rpi3:/home/pi# md5sum chromeboot-bricked.rom chromebook-broken.rom.3 1ef1d2230c27624661a86b57064057cb chromeboot-bricked.rom 1ef1d2230c27624661a86b57064057cb chromebook-broken.rom.3 # It really didn't change!
ch341a attempt
root@rpi3:/home/pi# flashrom --programmer ch341a_spi -r ch341a-snow-broken-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 ch341a_spi. Reading flash... done. root@rpi3:/home/pi# md5sum ch341a-snow-broken-spi.rom 1ef1d2230c27624661a86b57064057cb ch341a-snow-broken-spi.rom root@rpi3:/home/pi# md5sum *.rom 1ef1d2230c27624661a86b57064057cb ch341a-snow-broken-spi.rom 11e616f5dcf18d775f6484b78953ada0 chromebook-spi.rom 1ef1d2230c27624661a86b57064057cb chromeboot-bricked.rom root@rpi3:/home/pi# time flashrom --programmer ch341a_spi -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 ch341a_spi. Reading old flash chip contents... done. Erasing and writing flash chip... Erase/write done. Verifying flash... VERIFIED. real 5m21.170s user 0m48.300s sys 0m18.330s
https://dl.google.com/dl/edgedl/chromeos/recovery/linux_recovery.sh
u-boot
dpavlin@klin:/klin$ git clone git://git.denx.de/u-boot.git Cloning into 'u-boot'... remote: Counting objects: 442911, done. remote: Compressing objects: 100% (77033/77033), done. remote: Total 442911 (delta 360952), reused 440666 (delta 358805) Receiving objects: 100% (442911/442911), 93.64 MiB | 11.14 MiB/s, done. Resolving deltas: 100% (360952/360952), done. git remote add u-boot-samsung git://git.denx.de/u-boot-samsung.git git checkout u-boot-samsung/master -b u-boot-samsung/master dpavlin@klin:/klin/u-boot$ find . -name 'snow*' ./include/configs/snow.h ./configs/snow_defconfig export CROSS_COMPILE="arm-none-eabi-" ARCH=arm dpavlin@klin:/klin/u-boot$ make snow_defconfig HOSTCC scripts/basic/fixdep HOSTCC scripts/kconfig/conf.o SHIPPED scripts/kconfig/zconf.tab.c SHIPPED scripts/kconfig/zconf.lex.c SHIPPED scripts/kconfig/zconf.hash.c HOSTCC scripts/kconfig/zconf.tab.o HOSTLD scripts/kconfig/conf # # configuration written to .config # make
chromiumos
dpavlin@klin:/klin/chromebook/u-boot$ git remote -v origin https://chromium.googlesource.com/chromiumos/third_party/u-boot/ (fetch) origin https://chromium.googlesource.com/chromiumos/third_party/u-boot/ (push) dpavlin@klin:/klin/chromebook/u-boot$ git checkout -b firmware-snow-2695.B remotes/origin/firmware-snow-2695.B Branch firmware-snow-2695.B set up to track remote branch firmware-snow-2695.B from origin.
servo debug header
spi flash layout
dpavlin@nuc:/nuc/flashmap$ git remote -v origin https://github.com/dhendrix/flashmap (fetch) origin https://github.com/dhendrix/flashmap (push) dpavlin@nuc:/nuc/chromebook/flashmap$ ./fmap_decode /nuc/books/Chromebook/spi/snow-spi.rom | sort | grep -v R[OW]_ | grep -v WP_ area_offset="0x00000000" area_size="0x00002000" area_name="BL1 PRE_BOOT" area_flags_raw="0x01" area_flags="static" area_offset="0x00002000" area_size="0x00004000" area_name="BL2 SPL" area_flags_raw="0x01" area_flags="static" area_offset="0x00006000" area_size="0x0009a000" area_name="U_BOOT" area_flags_raw="0x01" area_flags="static" area_offset="0x000a0000" area_size="0x00001000" area_name="FMAP" area_flags_raw="0x01" area_flags="static" area_offset="0x000b0000" area_size="0x000ef000" area_name="GBB" area_flags_raw="0x01" area_flags="static" area_offset="0x00200000" area_size="0x00002000" area_name="VBLOCK_A" area_flags_raw="0x01" area_flags="static" area_offset="0x00202000" area_size="0x000edf00" area_name="FW_MAIN_A" area_flags_raw="0x01" area_flags="static" area_offset="0x00300000" area_size="0x00002000" area_name="VBLOCK_B" area_flags_raw="0x01" area_flags="static" area_offset="0x00302000" area_size="0x000edf00" area_name="FW_MAIN_B" area_flags_raw="0x01" area_flags="static" area_offset="0x003f8000" area_size="0x00004000" area_name="SHARED_DATA" area_flags_raw="0x01" area_flags="static" fmap_signature="0x5f5f464d41505f5f" fmap_ver_major="1" fmap_ver_minor="0" fmap_base="0x0000000000000000" fmap_size="0x400000" fmap_name="FMAP" fmap_nareas="23"
enable development mode from recovery
(parted) unit b (parted) print Model: MEM Drive Mini Metal (scsi) Disk /dev/sdc: 2021654528B Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 11 32768B 8421375B 8388608B RWFW 6 8421376B 8421887B 512B KERN-C 7 8421888B 8422399B 512B ROOT-C 9 8422400B 8422911B 512B reserved 10 8422912B 8423423B 512B reserved 2 10485760B 27262975B 16777216B KERN-A 4 27262976B 44040191B 16777216B KERN-B 8 44040192B 60817407B 16777216B ext4 OEM msftdata 12 127926272B 144703487B 16777216B fat16 EFI-SYSTEM boot, esp 5 144703488B 146800639B 2097152B ROOT-B 3 146800640B 1499463679B 1352663040B ext2 ROOT-A 1 1499463680B 1518338047B 18874368B ext2 STATE msftdata (parted) quit dpavlin@nuc:/nuc/flashmap$ ./enable_rw_mount.sh /dev/sdc 146800640B ./enable_rw_mount.sh: line 9: 146800640B: value too great for base (error token is "146800640B") enable_rw_mount called on non-ext2 filesystem: /dev/sdc 146800640B dpavlin@nuc:/nuc/flashmap$ ./enable_rw_mount.sh /dev/sdc 146800640 dpavlin@nuc:/nuc/flashmap$ sudo mount /dev/sdc3 /tmp/sdc3/
And this doesn't help to get recovery on broken cromebook working
upstream u-boot flashing
oot@rpi3:/home/pi# cp chromebook-spi.rom spi-mix.rom && dd conv=notrunc if=u-boot-nodtb.bin of=spi-mix.rom seek=`perl -e 'print 0x00006000'` 1163+1 records in 1163+1 records out 595496 bytes (595 kB) copied, 0.0177353 s, 33.6 MB/s root@rpi3:/home/pi# time flashrom --programmer ch341a_spi --layout snow.layout2 --image U_BOOT --write spi-mix.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 Using region: "U_BOOT". Calibrating delay loop... OK. Found GigaDevice flash chip "GD25LQ32" (4096 kB, SPI) on ch341a_spi. Reading old flash chip contents... done. Erasing and writing flash chip... Erase/write done. Verifying flash... VERIFIED. real 3m31.555s user 0m21.310s sys 0m13.660s
building chromiumos
dpavlin@klin:/klin/chromebook$ . env.sh
dpavlin@klin:/klin/chromebook/chromiumos$ cros_sdk --download
(cr) ((971c906...)) dpavlin@klin ~/trunk/src/scripts $ export BOARD=daisy
(cr) ((971c906...)) dpavlin@klin ~/trunk/src/scripts $ ./set_shared_user_password.sh
Enter password for shared user account: Password set in /etc/shared_user_passwd.txt
(cr) ((971c906...)) dpavlin@klin ~/trunk/src/scripts $ ./build_packages --board=${BOARD}
breaks
building u-boot
BOARD=daisy
FDT=snow
cros_workon --board=${BOARD} start chromeos-u-boot
emerge-${BOARD} chromeos-ec chromeos-u-boot chromeos-bootimage
boot resistors (boot from sd card)
coreboot
dpavlin@klin:/klin/coreboot/util/crossgcc$ ./buildgcc -p armv7a-eabi -j 4
