[Galaxy Note II Q&A, Help & Troubleshooting] eagebhart:
I'm posting this in the hope that it will help someone else. The problems I've had are different enough from other threads that this story could provide some clues for someone else. I am also using a mac, so I'm using Heimdall instead of Odin.

I have an sph-l900, galaxy note 2, on Credo Mobile which is on the Sprint network - obviously.

1. My phone started acting strangely and at some point no longer had a carrier. Red X next to the signal meter.

2. Under Status, IMEI and everything else was unknown.

Everything I read said to reset the phone to a stock rom.

Since I had TWRP, I just tried flashing the usual way from the external sdcard. What I noticed is that I was getting an error on wipe,

'can not mount /data' - this is the big clue I didn't see for a while. It's the cause of bootloops after a flash from TWRP and the cause

of the lost network.

This meant that no matter what I did, When I flashed from TWRP I got a bootloop because the Dahlvik cache was not wiped.

I had to resort to putting the phone in odin mode, and use heimdall to flash all the images.

I made a shell command out of this:

heimdall flash --RECOVERY recovery.img --CACHE cache.img --HIDDEN hidden.img --SYSTEM system.img --TOMBSTONES tombstones.img --RADIO modem.bin --BOOT boot.img --PARAM param.bin --TZSW tz.img --BOOTLOADER sboot.bin --no-reboot --verbose

You can use 'heimdall print-pit' to find out what your partition names are. They are probably uppercase like mine.

Finally I'm booting, but still no carrier. I put TWRP back and tried to mount /data. Still no good.

This means that this rom is where I'm stuck until I can get /data mounting again.

Then I added --repartition --pit T0LTE.pit to my heimdall command. This failed every time. Although repartition was clearly what I needed.

Finally, I removed the --repartition, got it working without /data so I could connect using ADB shell to try repairing /data.

1. cd /etc

2. df to see the file systems. /data is clearly missing.

/etc # df

Filesystem 1K-blocks Used Available Use% Mounted on

tmpfs 916024 136 915888 0% /dev

tmpfs 916024 20 916004 0% /tmp

tmpfs 916024 0 916024 0% /storage

tmpfs 916024 0 916024 0% /mnt/secure

tmpfs 916024 0 916024 0% /mnt/fuse

/dev/block/mmcblk0p12

1290112 40712 1249400 3% /cache

3. cat fstab or vold.fstab on older systems -- shows the mountpoints. So I could determine that /data was /dev/block/mmcblk0p16

/etc # cat fstab

/dev/block/mmcblk0p12 /cache ext4 rw

/dev/block/mmcblk0p16 /data ext4 rw

/dev/block/mmcblk0p13 /system ext4 rw

/dev/block/mmcblk0p14 /preload ext4 rw

4. Try to run file system check.

/etc # /sbin/e2fsck /dev/block/mmcblk0p16

e2fsck 1.41.14 (22-Dec-2010)

/sbin/e2fsck: Superblock invalid, trying backup blocks...

/sbin/e2fsck: Bad magic number in super-block while trying to open /dev/block/mmcblk0p16

The superblock could not be read or does not describe a correct ext2

filesystem. If the device is valid and it really contains an ext2

filesystem (and not swap or ufs or something else), then the superblock

is corrupt, and you might try running e2fsck with an alternate superblock:

e2fsck -b 8193 <device>

4. Get info about the file system. with make file system.

/etc # /sbin/mke2fs -n /dev/block/mmcblk0p16

mke2fs 1.41.14 (22-Dec-2010)

Filesystem label=

OS type: Linux

Block size=1024 (log=0)

Fragment size=1024 (log=0)

Stride=0 blocks, Stripe width=0 blocks

5136 inodes, 20480 blocks

1024 blocks (5.00%) reserved for the super user

First data block=1

Maximum filesystem blocks=20971520

3 block groups

8192 blocks per group, 8192 fragments per group

1712 inodes per group

Superblock backups stored on blocks:

8193

5. Try file system check with the superblock backup.

/etc # /sbin/e2fsck -b 8193 /dev/block/mmcblk0p16

e2fsck 1.41.14 (22-Dec-2010)

/sbin/e2fsck: Invalid argument while trying to open /dev/block/mmcblk0p16

The superblock could not be read or does not describe a correct ext2

filesystem. If the device is valid and it really contains an ext2

filesystem (and not swap or ufs or something else), then the superblock

is corrupt, and you might try running e2fsck with an alternate superblock:

e2fsck -b 8193 <device>

6. I have no choice but to try to restore the superblocks. mke2fs with -S will try to do that. I added the block size and groups

from the previous report, but I don't think they were necessary.

etc # mke2fs -b 1024 -g 8192 -S /dev/block/mmcblk0p16

mke2fs 1.41.14 (22-Dec-2010)

Filesystem label=

OS type: Linux

Block size=1024 (log=0)

Fragment size=1024 (log=0)

Stride=0 blocks, Stripe width=0 blocks

5136 inodes, 20480 blocks

1024 blocks (5.00%) reserved for the super user

First data block=1

Maximum filesystem blocks=20971520

3 block groups

8192 blocks per group, 8192 fragments per group

1712 inodes per group

Superblock backups stored on blocks:

8193

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 37 mounts or

180 days, whichever comes first. Use tune2fs -c or -i to override.

7. Run file system check again to repair any damage. Answer y to any questions.

/etc # /sbin/e2fsck /dev/block/mmcblk0p16

e2fsck 1.41.14 (22-Dec-2010)

/dev/block/mmcblk0p16 contains a file system with errors, check forced.

Resize inode not valid. Recreate<y>? y

yes

Pass 1: Checking inodes, blocks, and sizes

Root inode is not a directory. Clear<y>? yes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Root inode not allocated. Allocate<y>? y

yes

/lost+found not found. Create<y>? yes

Pass 4: Checking reference counts

Pass 5: Checking group summary information

Block bitmap differences: +(1--298) +(8193--8489) +(16385--16600)

Fix<y>? y

yes

Free blocks count wrong for group #0 (7893, counted=7892).

Fix<y>? yes

Free blocks count wrong (19667, counted=19666).

Fix<y>? y

yes

Inode bitmap differences: +1 +(3--10)

Fix<y>? yes

Free inodes count wrong for group #0 (1711, counted=1701).

Fix<y>? y

yes

Directories count wrong for group #0 (1, counted=2).

Fix<y>? yes

Free inodes count wrong (5135, counted=5125).

Fix<y>? y

yes

/dev/block/mmcblk0p16: ***** FILE SYSTEM WAS MODIFIED *****

/dev/block/mmcblk0p16: 11/5136 files (0.0% non-contiguous), 814/20480 blocks

8. Mount data and check to see everything is ok.

/etc # mount /data

/etc # df

Filesystem 1K-blocks Used Available Use% Mounted on

tmpfs 916024 136 915888 0% /dev

tmpfs 916024 20 916004 0% /tmp

tmpfs 916024 0 916024 0% /storage

tmpfs 916024 0 916024 0% /mnt/secure

tmpfs 916024 0 916024 0% /mnt/fuse

/dev/block/mmcblk0p12

1290112 40712 1249400 3% /cache

/dev/block/mmcblk0p16

19827 161 18642 1% /data

9. Exit, reboot to Odin mode, Reflash the ROM with heimdall/odin just like before. - leave off the --repartition --pit...

10. Reboot.

I now have an almost working phone. It actually has a network connection. It would be safe at this point to call your phone service

tech support and have them walk you through setting up your phone again.

I do not know what it takes for other phones, but with the note 2, I removed the battery while it was booted up to force an network update.

This gave me a new PRL and set my phone number along with everything else. I now had a working phone,

but for some reason no data service.

11. Turn off wifi, update profile. I get session in progress error.

12. Remove battery while booted, wifi off.

13. Reboot. update profile again. data network established.

That's pretty much it. In a nutshell, I had a corrupt filesystem on /data. The initial indicator of this was no carrier signal with an X on it.

This also caused bootloops when reflashing from TWRP/CWM.

Restoring the /data filesystem and flashing a stock rom restored the carrier and allowed a PRL and Profile update to get the phone working again.

Don't turn on wifi right away, let the phone update the PRL and Profile, and get everything working first.