I'm going through this atm. I've actually forgotten my disk password.
I installed the fel boot mode onto the sdcard and plugged in the usb cable and powered on.
https://linux-sunxi.org/FEL#Through_a_sp...card_image
On my computer (usb host) I run.
$> dmesg -w &
usb 1-2: new full-speed USB device number 74 using xhci_hcd
$> ./boot-tools/sunxi-tools/sunxi-fel -l
USB device 001:074 Allwinner A64 92c089ba:24204620:78f4c71c:0c030710
$> cd boot-tools && make pinebook_ums
Code:
usb 1-2: New USB device found, idVendor=0bb4, idProduct=0fff, bcdDevice= 2.00
usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 1-2: Product: AllWinner Technology
usb 1-2: Manufacturer: 20101201120001
usb 1-2: SerialNumber: USB Mass Storage
usb-storage 1-2:1.0: USB Mass Storage device detected
scsi host5: usb-storage 1-2:1.0
scsi 5:0:0:0: Direct-Access USB2.0 USB Storage 0100 PQ: 0 ANSI: 2
sd 5:0:0:0: Attached scsi generic sg4 type 0
sd 5:0:0:0: [sdd] 61071360 512-byte logical blocks: (31.3 GB/29.1 GiB)
sd 5:0:0:0: [sdd] Write Protect is off
sd 5:0:0:0: [sdd] Mode Sense: 03 00 00 00
sd 5:0:0:0: [sdd] No Caching mode page found
sd 5:0:0:0: [sdd] Assuming drive cache: write through
sdd: sdd1 sdd3
Then I can try to unlock the partition using cryptdisk
$>cryptsetup isLuks /dev/sdd1 && echo $?
1
$>cryptsetup isLuks /dev/sdd1 && echo $?
0
$>cryptsetup luksOpen /dev/sdd3 mobian
If all else fails then reinstall.