My situation
I have been using the encryption of my Android phone’s external SD Card on a Samsung Galaxy J3 (2017) Duos (SM-J330F) ever since I got it. I have recently updated my OS to Android 8.0 (Oreo).
Upon restart a notification was displayed that the encrypted SD card could not be decrypted because it was encrypted on a different device (which is no true; I have been using the same device, but the OS might not be able to recognize this). It is my understanding that decryption of the SD card is not possible on any other device.
This might not be the first case where Android fails to decrypt SD card after update to Oreo.
What have I tried?
I have shutdown my device, removed the (micro) SD card, and plugged it in to my notebook. All (?) files are visible, the filenames look okay, but content is not readable. I have then created an image by running
dd if=/dev/mmcblk0p1 of=~/SANDISKSDHC.img status=progress
I have reformatted the SD card with my Android device. I have then written back the IMG file to the SD card by running
dd if=~/SANDISKSDHC.img of=/dev/mmcblk0p1 status=progress
I have loaded the SD card into my Android device and started it. Again a notification was displayed that the encrypted SD card could not be decrypted because it was encrypted on a different device...
My resources
- How do I decrypt files on my SD card that I encrypted using the Settings? (doesn't seem to apply to my situation)
- Encrypted SD card failed after S5 restart (different situation, but references the next)
- How to decrypt a microSD card after a factory reset of the device used to encrypt it? (tried this, did not solve my problem)
- Cannot open Airwatch encrypted files on SD card after Android update (no answer)
- How to Read marshmallow encrypted memory card? (different situation, and I did not understand the procedure linked in the answer)
- How to restore files on SD Card that was protected by Vault app? (different situation)
