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Flashing my Nexus 7

I did a complete re-install of my years-old Nexus 7 2012 this morning after it choked on an upgrade and got stuck at boot time. Notes for posterity:

Links and downloads:

  • instructions from this page.
  • adb and fastboot: Google now release 'latest' packages so dodgy scripts on the net are no longer needed (announcement, direct).
  • download images directly from Google (I went with nakasi 5.1.1. If it remains sluggish may go back to Kit Kat).


  • unzipped adb and fastboot into c:/android-sdk/platform-tools. I don't imagine location has to be that, but that's what the instructions said so I went with it

  • unzip image and make sure files are in same directory (ie. same dir as fastboot.exe).

  • reboot Nexus into boot loader (power off, then hold Volume Down while pressing power button).

  • plug in USB cable

  • open command prompt in the platform-tools dir.

  • run the following:

    fastboot erase boot
    fastboot erase cache
    fastboot erase recovery
    fastboot erase system
    fastboot erase userdata
    fastboot oem unlock 
    fastboot flash bootloader bootloader-grouper-4.23.img 
    fastboot reboot-bootloader 
    fastboot -w update
  • reboot into bootloader again

  • run

    fastboot oem lock
  • reboot.

Worked like a charm for me. Full output:

C:\android-sdk\platform-tools>fastboot erase boot
< waiting for any device >
erasing 'boot'...
OKAY [  0.080s]
finished. total time: 0.085s

C:\android-sdk\platform-tools>fastboot erase cache
******** Did you mean to fastboot format this ext4 partition?
erasing 'cache'...
OKAY [  0.116s]
finished. total time: 0.119s

C:\android-sdk\platform-tools>fastboot erase recovery
erasing 'recovery'...
OKAY [  0.026s]
finished. total time: 0.028s

C:\android-sdk\platform-tools>fastboot erase system
******** Did you mean to fastboot format this ext4 partition?
erasing 'system'...
OKAY [  0.558s]
finished. total time: 0.560s

C:\android-sdk\platform-tools>fastboot erase userdata
******** Did you mean to fastboot format this ext4 partition?
erasing 'userdata'...
OKAY [  7.542s]
finished. total time: 7.544s

C:\android-sdk\platform-tools>fastboot oem unlock
(bootloader) erasing userdata...
(bootloader) erasing userdata done
(bootloader) erasing cache...
(bootloader) erasing cache done
(bootloader) unlocking...
(bootloader) Bootloader is unlocked now.
OKAY [ 25.253s]
finished. total time: 25.256s

C:\android-sdk\platform-tools>fastboot flash bootloader bootloader-grouper-4.23.img
target didn't report max-download-size
sending 'bootloader' (2100 KB)...
OKAY [  0.275s]
writing 'bootloader'...
OKAY [  1.234s]
finished. total time: 1.513s

C:\android-sdk\platform-tools>fastboot reboot-bootloader
rebooting into bootloader...
OKAY [  0.015s]
finished. total time: 0.017s

C:\android-sdk\platform-tools>fastboot -w update
target didn't report max-download-size
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
archive does not contain 'vendor.img'
wiping userdata...
Creating filesystem with parameters:
    Size: 30080499712
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 8160
    Inode size: 256
    Journal blocks: 32768
    Blocks: 7343872
    Block groups: 225
    Reserved block group size: 1024
Created filesystem with 11/1836000 inodes and 159268/7343872 blocks
wiping cache...
Creating filesystem with parameters:
    Size: 464519168
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 7088
    Inode size: 256
    Journal blocks: 1772
    Blocks: 113408
    Block groups: 4
    Reserved block group size: 31
Created filesystem with 11/28352 inodes and 3654/113408 blocks
Bootloader Version...: 4.23
Baseband Version.....: N/A
Serial Number........: 015d25785843f405
checking product...
OKAY [  0.031s]
checking version-bootloader...
OKAY [  0.017s]
sending 'boot' (5184 KB)...
OKAY [  0.662s]
writing 'boot'...
OKAY [  0.217s]
sending 'recovery' (5738 KB)...
OKAY [  0.736s]
writing 'recovery'...
OKAY [  0.238s]
erasing 'system'...
OKAY [  0.115s]
sending 'system' (649455 KB)...
OKAY [ 81.590s]
writing 'system'...
OKAY [ 36.336s]
erasing 'userdata'...
OKAY [  4.909s]
sending 'userdata' (139157 KB)...
OKAY [ 17.318s]
writing 'userdata'...
OKAY [ 12.632s]
erasing 'cache'...
OKAY [  0.089s]
sending 'cache' (9052 KB)...
OKAY [  1.141s]
writing 'cache'...
OKAY [  1.080s]

finished. total time: 157.261s

C:\android-sdk\platform-tools>fastboot oem lock
(bootloader) Bootloader is locked now.
OKAY [  1.430s]
finished. total time: 1.433s


{2017.01.08 13:02}


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