#Burn the image to the media if you haven't already
xzcat devuan.img.xz | dd of=/dev/mmcblk0       

#Look at the partition table to make sure things turned out well
fdisk -l

#Run parted
parted /dev/mmcblk0                                       

#This was a step that was solved for me by the lovely people at Kali's forum. They have a lot of documentation about this
(parted) p                                You'll be asked if you want to fix it, type Fix and exit out of the program
#You're looking for the [b]sec gpt table[/b] row and you're looking under the [b]start[/b] column for a number mine was 61765599 this 
cgpt show /dev/mmcblk0         went into [i]secgptstart[/i] in the next step

#Extend the data
cgpt add -i 2  -t data -b 40960 -s `expr [i]secgptstart[/i] - 40960` -l Root /dev/mmcblk0               #These are tildes not comma's where the expression is.
cgpt repair /dev/mmcblk0

#Make it bootable
cgpt add -i 1 -S 1 -T 5 -P 10 -l KERN-A /dev/mmcblk0
cgpt add -i 2 -S 1 -T 5 -P 5 -l KERN-B  /dev/mmcblk0