[Nexus 10 Q&A, Help & Troubleshooting] markodonohue:
After update about 6 months ago I got errors on my Nexus 10. It was stuck in the boot animation thing.

Booting to the recovery menu and trying things like, clear cache, etc gives the failed to mount cache errors eg:

E:failed to mount /cache (Invalid argument)

E: Can't mount /cache/recovery/log

E: Can't open /cache/recovery/log

E:failed to mount /cache (Invalid argument)

E: Can't mount /cache/recovery/last_log

E: Can't open /cache/recovery/last_log

E:failed to mount /cache (Invalid argument)

E: Can't mount /cache/recovery/last_install

E: Can't open /cache/recovery/last_install

E:failed to mount /cache (Invalid argument)

E: Can't mount /cache/recovery/last_kmsg

E: Can't open /cache/recovery/last_kmsg

​

But it seems without cache, and since it is oem locked I am caught in catch-22.

Since to do oem unlock, or sideload, or recovery menu options, they all hang - I suspect because it is trying to put some file in cache directory.

For fastboot oem unlock

I can connect to it via fastboot, and try

fastboot oem unlock

which brings up the Yes/No screen on the Nexus 10, I can navigate with the volume, select Yes or No, but if I select Yes, it hangs - I suspect it is hanging doing the user wipe (although I've done that a heap anyway). Need to restart it <pwr> <vol+> <vol-> to get back to boot menu.

<screenshot coming - need to wait 10hrs>

h t t p s :/ /drive.google.com/open?id=0B6cJseueu7P6enNpbFR5cFFXN1BNbjg3UWVkMDNvb0ZhNV9B

Clearly the Power button works, since I used it to navigate to this screen, and others, and works when I press No - so pressing Yes hangs for some other reason.

​

For sideload

when I select recover menu "load update from adb" then run

C:\...\platform-tools>adb sideload mantaray-lmy49j-factory-b24f40e6.zip

It gives details of loading on the tablet screen, along with errors about mounting /cache and then goes back to the recovery menu.

​

Erase userdata & cache seem to work

C:\...\platform-tools>fastboot erase userdata

******** Did you mean to fastboot format this ext4 partition?

Erasing 'userdata' OKAY [ 3.025s]

Finished. Total time: 3.034s

C:\...\platform-tools>fastboot erase cache

******** Did you mean to fastboot format this ext4 partition?

Erasing 'cache' OKAY [ 3.018s]

Finished. Total time: 3.049s​

But formatting them requires unlock

C:\Users\odoma04\AppData\Local\Android\Sdk\platform-tools>fastboot format:ext4 cache

mke2fs 1.44.3 (10-July-2018)

Creating filesystem with 135168 4k blocks and 33840 inodes

Filesystem UUID: 83b1b5c6-1224-11e9-aa85-856a55f9d0b8

Superblock backups stored on blocks:

32768, 98304

Allocating group tables: done

Writing inode tables: done

Creating journal (4096 blocks): done

Writing superblocks and filesystem accounting information: done

Sending 'cache' (200 KB) OKAY [ 0.032s]

Writing 'cache' FAILED (remote: 'Locked - Use "fastboot oem unlock" to Unlock')

Finished. Total time: 0.119s
​

Nexus Settings

C:\...\platform-tools>fastboot getvar all

(bootloader) variant: wifi-only

(bootloader) serialno: R32XXXX

(bootloader) version-hardware: 8

(bootloader) version-bootloader: MANTAMF01

(bootloader) secure: yes

(bootloader) unlocked: no

(bootloader) off-mode-charge: enabled(1)

(bootloader) signing: yes

(bootloader) boot partition- type: raw, size: 0x0000000001000000

(bootloader) recovery partition- type: raw, size: 0x0000000001ff0000

(bootloader) metadata partition- type: raw, size: 0x0000000000010000

(bootloader) misc partition- type: raw, size: 0x0000000000400000

(bootloader) cache partition- type: ext4, size: 0x0000000021000000

(bootloader) system partition- type: ext4, size: 0x0000000032000000

(bootloader) userdata partition- type: ext4, size: 0x0000000352c00000

all:

Finished. Total time: 0.033s​

So I suspect if I had : (bootloader) unlocked: yes

I would be ok, without it I don't have any options to reset the cache or the device.

Questions :

a) so what is the invalid parameter on the mount command ?

(mount is pretty simple, on unix, the partition seems to be ext4, so is it possible my mount table had ext2 or something since it was older version ? )

b) any way to run adb when the system doesn't come up, so can at least go have a look at the system files with shell etc ?

c) any way to check the memory - maybe I have a mem chip failure ?

And of course any other ideas welcome, hate to junk something that worked well & seems to have got caught with just some update (or out of memory issue ) going wrong.

Thanks in advance.

Cheers - Mark