[Swlug] mount disk image file with encryption

[bascule]

i have a failing microsd card, i've made an image of it but i can't find the 
right arguments to access the contents of the image file.

the card is adopted storage from an android phone and i have the key, using 
the physical card i can access it using:
dmsetup create crypt1 --table "0 `blockdev --getsize /dev/sdf2` crypt aes-cbc-
essiv:sha256 `cat key` 0 /dev/sdf2 0"

and then mounting.

but while fdisk sdcard_img shows:
[root at mycroft bascule]# fdisk sdcard_img

Welcome to fdisk (util-linux 2.33.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.


Command (m for help): p
Disk sdcard_img: 119.8 GiB, 128579534848 bytes, 251131904 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: B826F4C0-DC80-4670-A4A7-F99A7314FF9F

Device      Start       End   Sectors   Size Type
sdcard_img1  2048     34815     32768    16M unknown
sdcard_img2 34816 251131870 251097055 119.7G unknown


i don't know how to reference the 2nd 'partition' on the image file for the 
dmsetup command.
since making the image file the card seems to be failing more and more so i 
wish to extract files from the image file
can someone help me?

bascule