swap-adoptable-storage

How to swap adoptable storage SD card on Android 7 (Nougat)

I'm using a Samsung Galaxy S7 with Android 7.1.2 for a long time. I started with a 8 GB SD card as adoptable storage. That was fine until the missing space on the SD card become more and more a pain. So I ordered a 128 GB SD card and tried to move all my stuff from 8 GB SD card to 128 GB SD card.

All the ways I could image didn't work, like

• Just dd the discs
• luks encryption

So here comes a guide how to swap the adoptable storage SD card on Android 7. This guide was made in the context of

• Target
  • Samsung Galaxy S7
  • Android 7.1.2
• Host
  • Linux Mint 19.3 Tricia

In my case the device /dev/sde is the SD card slot on the host.

0. Get unique GUID and partition GUID code of your current disk:
   

1. Make a backup of your current SD card
   $ sudo dd if=/dev/sde of=SamsungGalaxyS7_8GB_InternalStorage.img.bin bs=1M status=progress

2. dd the image to your new SD card
   $ sudo dd if=SamsungGalaxyS7_8GB_InternalStorage.img.bin of=/dev/sde bs=1M status=progress

3. For the next step you need a patched gdisk

4. Get the source of gdisk - more information can be found here (german): https://www.android-hilfe.de/forum/android-6-0-x-marshmallow.2417/adopted-sd-partition-vergroessern.823463.html
   $ apt-get source gdisk

5. Patch parttypes.cc according to - the partition GUID code must match the GUID of android_expand partition of the old disk (see above)

     $ diff -Naur gdisk-1.0.3/parttypes.cc /usr/src/gdisk-1.0.3/parttypes.cc 
     --- gdisk-1.0.3/parttypes.cc	2017-07-28 03:41:20.000000000 +0200
     +++ /usr/src/gdisk-1.0.3/parttypes.cc	2020-09-06 19:49:11.614131088 +0200
     @@ -263,6 +263,8 @@
         // A straggler Linux partition type....
         AddType(0xfd00, "A19D880F-05FC-4D3B-A006-743F0F84911E", "Linux RAID");
   
     +   AddType(0xffff, "193D1EA4-B3CA-11E4-B075-10604B889DCF", "-->Unkown<--");
     +
         // Note: DO NOT use the 0xffff code; that's reserved to indicate an
         // unknown GUID type code.
      } // PartType::AddAllTypes()
   

6. Use the patched gdisk to expand the partition
   $ sudo gdisk /dev/sde

7. After start of gdisk
   
   It might be the case that the kernel complains that the GPT is inconsistent. In this case call gparted and correct the error by accepting the bigger partition table.

8. Delete android_expand partition
   

9. Create a new partition - ensure that the new size matches the size of the new SD card (128 GB in my case)
   

10. Switch to expert menu and set the newly created partition GUID to the same of the old disk:
    

11. Return to main menu and change partition name
    

12. Verify that your partition matches the size of the new disk
    

13. Write new partition table to disk
    

14. Decrypt newly created partition
    $ sudo dmsetup create crypt1 --table "0 $(sudo blockdev --getsize /dev/sde2) crypt aes-cbc-essiv:sha256 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 0 /dev/sde2 0"
    The xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx is the key to decrypt the partition. How to get the key is explained here: https://nelenkov.blogspot.com/2015/06/decrypting-android-m-adopted-storage.html

15. Check the decrypted partition for errors:

     $ sudo e2fsck -f /dev/mapper/crypt1
     e2fsck 1.44.1 (24-Mar-2018)
     Pass 1: Checking inodes, blocks, and sizes
     Pass 2: Checking directory structure
     Pass 3: Checking directory connectivity
     Pass 4: Checking reference counts
     Pass 5: Checking group summary information
     /dev/mapper/crypt1: 3046/484800 files (14.1% non-contiguous), 1693456/1936123 blocks
    

16. Resize the partition

     $ sudo resize2fs /dev/mapper/crypt1
     resize2fs 1.44.1 (24-Mar-2018)
     Resizing the filesystem on /dev/mapper/crypt1 to 31212795 (4k) blocks.
     The filesystem on /dev/mapper/crypt1 is now 31212795 (4k) blocks long.
    

17. I checked the resized partition for errors twice:

     $ sudo e2fsck -f /dev/mapper/crypt1
     e2fsck 1.44.1 (24-Mar-2018)
     Pass 1: Checking inodes, blocks, and sizes
     Inode 7, i_size is 2009149440, should be 2013372416.  Fix<y>? yes
     Pass 2: Checking directory structure
     Pass 3: Checking directory connectivity
     Pass 4: Checking reference counts
     Pass 5: Checking group summary information
     
     /dev/mapper/crypt1: ***** FILE SYSTEM WAS MODIFIED *****
     /dev/mapper/crypt1: 3046/7700240 files (14.1% non-contiguous), 2149093/31212795 blocks
    
    
    
     $ sudo e2fsck -f /dev/mapper/crypt1
     e2fsck 1.44.1 (24-Mar-2018)
     Pass 1: Checking inodes, blocks, and sizes
     Pass 2: Checking directory structure
     Pass 3: Checking directory connectivity
     Pass 4: Checking reference counts
     Pass 5: Checking group summary information
     /dev/mapper/crypt1: 3046/7700240 files (14.1% non-contiguous), 2149093/31212795 blocks
    

18. Unmap the decrypted partition
    $ sudo dmsetup remove /dev/mapper/crypt1

Finally you have a lot of free space: