Boot loop after flashing android 6.0 marshmallow on nexus 5 follow up this question follows up on this one (but there are many other posts about this topic on the web.. see this reddit post and this xda developers post.

I just want to approach this problem in a more structured way as opposed to just saying how something worked by coincidence.

Problem definition

Like everyone else I simply followed the official instructions from google developers. To expand a bit (because this could be the cause of the problem).. following this part of the instruction from the above link:


  To flash a device using one of the system images below (or one of your own), you need the fastboot tool. You can get the fastboot tool either:  
  
  
  From a compiled version of the the Android Open Source Project.  
  Or, from the platform-tools/ directory in the Android SDK. Be sure that you have the latest version of the Android SDK Platform-tools from the SDK Manager.
  


So I simply downloaded the entire android studio application (i know that's a bit of overkill but I just wanted to make sure I got the latest and greatest)

From the below android studio screenshot.. you can see that I have android SDK platform tools 23.0.1 

question: I'm updating my phone from android 5.0.x (not sure what the exact version is).. could it be that this android version mismatches the android platform tools that i have?



I've ensured that my fastboot is added to my PATH environment:

$ which fastboot
/Users/abdullahbakhach/Library/Android/sdk/platform-tools/fastboot


I've downloaded the flash file (specifically the hammerhead for nexux 6.0.0 (MRA58K)).. then i started the device in fastboot mode by the key combination. and ran the flash-all script.

what happened was that the script ran with the following logs:

$ ./flash-all.sh 
sending 'bootloader' (3120 KB)...
OKAY [  0.207s]
writing 'bootloader'...
OKAY [  0.524s]
finished. total time: 0.731s
rebooting into bootloader...
OKAY [  0.001s]
finished. total time: 0.001s
sending 'radio' (45425 KB)...
OKAY [  1.536s]
writing 'radio'...
OKAY [  3.145s]
finished. total time: 4.681s
rebooting into bootloader...
OKAY [  0.001s]
finished. total time: 0.001s
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: HHZ12k
Baseband Version.....: M8974A-2.0.50.2.27
Serial Number........: 03a3d66d0a4e64bd
--------------------------------------------
checking product...
OKAY [  0.100s]
checking version-bootloader...
OKAY [  0.100s]
checking version-baseband...
OKAY [  0.100s]
sending 'boot' (9156 KB)...
OKAY [  0.500s]
writing 'boot'...
OKAY [  0.798s]
sending 'recovery' (10016 KB)...
OKAY [  0.562s]
writing 'recovery'...
OKAY [  0.850s]
sending 'system' (1019261 KB)...
OKAY [ 32.164s]
writing 'system'...
OKAY [ 70.421s]
erasing 'userdata'...
OKAY [ 15.854s]
erasing 'cache'...
OKAY [  0.630s]
rebooting...

finished. total time: 122.480s


question: should i be concerned about this part?

archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'


anyways after all is done.. the phone reboots and gets stuck in the boot screen (for ever).. 

what i've tried

I've tried running these commands as suggested by this post 

adb shell
e2fsck /dev/block/platform/msm_sdcc.1/by-name/persist


and 

make_ext4fs /dev/block/platform/msm_sdcc.1/by-name/persist


but nothing changed.. 

I've also tried performing a wipe using TWRP as suggested by this post:
- I downloaded the twrp-2.8.7.1-hammerhead.dmg file from the twrp site 

and then ran 

fastboot flash recovery twrp-2.8.7.1-hammerhead.dmg


then performed a wipe two different ways:
- performing a normal wipe pretty much made things worse.. the phone would show the google logo then reboot.. show the google logo and so on
- simply deleting the cache also didn't make any difference at all..

i'm stuck.. any suggestions?
I too faced this issue and issuing the fastboot commands manually (instead of relying on flash-all) and it worked well.

These are the commands to use (just forget everything and make sure these commands are executed in this order with the appropriate .img file available):

fastboot flash recovery recovery.img
fastboot flash boot boot.img
fastboot flash cache cache.img
fastboot flash userdata userdata.img
fastboot flash system system.img
fastboot reboot