no adb devices detected after failed revert to Android Just a few days ago I tried to revert my Asus Nexus 7 wifi back to Android from Ubuntu Touch Preview and made a mistake somewhere. To sum up, now my device has no OS on it so it will only show the bootloader, and it does not show up as an adb device but still shows on fastboot. Here's a summary


Downloaded Android 4.2.2 nakasi via https://developers.google.com/android/nexus/images#nakasi
followed instructions from https://wiki.ubuntu.com/Nexus7/Installation#Returning_your_Nexus_7_to_Stock_Android
failed on step "writing 'radio'". Also got: archive does not contain 'boot.sig', archive does not contain 'recovery.sig', archive does not contain 'system.sig'
tried multiple times with the same errors.
got frustrated and restarted to try again
now I have a blank list of adb devices


Anyone have advice on where I can learn to fix this or want to help with some suggestions? Thanks for your help!
Just did all the necessary steps on my N7:


Download the factory image from Google
Unpack the downloaded file (e.g. by tar -xvzf nakasi-jdq39-factory-c317339e.tgz)
Boot your N7 into the bootloader (hold the power and both volume buttons)
Have fastboot installed (comes with the SDK or for Ubuntu, just install android-tools-fastboot)
connect it to your machine
Flash it using flash-all.bat or flash-all.sh (needs installed fastboot)


Here's the transcript (using Ubuntu):

me@localhost:/tmp/nakasi-jdq39$ ls
bootloader-grouper-4.18.img  flash-all.sh   image-nakasi-jdq39.zip
flash-all.bat                flash-base.sh
me@localhost:/tmp/nakasi-jdq39$ bash flash-all.sh 
...
(bootloader) Bootloader is already unlocked
OKAY [  0.020s]
finished. total time: 0.020s
erasing 'boot'...
OKAY [  0.104s]
finished. total time: 0.104s
******** Did you mean to fastboot format this partition?
erasing 'cache'...
OKAY [  0.147s]
finished. total time: 0.147s
erasing 'recovery'...
OKAY [  0.106s]
finished. total time: 0.106s
******** Did you mean to fastboot format this partition?
erasing 'system'...
OKAY [  0.175s]
finished. total time: 0.175s
******** Did you mean to fastboot format this partition?
erasing 'userdata'...
OKAY [  1.401s]
finished. total time: 1.401s
sending 'bootloader' (2096 KB)...
OKAY [  0.286s]
writing 'bootloader'...
OKAY [  1.165s]
finished. total time: 1.452s
rebooting into bootloader...
OKAY [  0.020s]
finished. total time: 0.020s
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: 4.18
Baseband Version.....: N/A
Serial Number........: XXXXXXXXXXXXXXXXXX
--------------------------------------------
checking product...
OKAY [  0.040s]
checking version-bootloader...
OKAY [  0.023s]
sending 'boot' (4944 KB)...
OKAY [  0.654s]
writing 'boot'...
OKAY [  0.172s]
sending 'recovery' (5446 KB)...
OKAY [  0.712s]
writing 'recovery'...
OKAY [  0.193s]
erasing 'system'...
OKAY [  0.055s]
sending 'system' (471804 KB)...
OKAY [ 60.282s]
writing 'system'...
OKAY [ 23.357s]
erasing 'userdata'...
OKAY [  1.023s]
formatting 'userdata' partition...
Creating filesystem with parameters:
    Size: 14442037248
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 8176
    Inode size: 256
    Journal blocks: 32768
    Label: 
    Blocks: 3525888
    Block groups: 108
    Reserved block group size: 863
Created filesystem with 11/883008 inodes and 96825/3525888 blocks
sending 'userdata' (137526 KB)...
writing 'userdata'...
OKAY [ 27.078s]
erasing 'cache'...
OKAY [  0.050s]
formatting 'cache' partition...
Creating filesystem with parameters:
    Size: 464519168
    Block size: 4096
    Blocks per group: 32768
    Inodes per group: 7088
    Inode size: 256
    Journal blocks: 1772
    Label: 
    Blocks: 113408
    Block groups: 4
    Reserved block group size: 31
Created filesystem with 11/28352 inodes and 3654/113408 blocks
sending 'cache' (9052 KB)...
writing 'cache'...
OKAY [  1.751s]
rebooting...

finished. total time: 115.545s