Android Encryption porting I'm currently trying to enable the full disk encryption in Android on my custom board. 
Some informations:


The /data Partition is the 4th Partition on my SD Card. 
after the /data Partition there is >2MB free space
the /data Partition is ext4


If I run vdc cryptfs enablecrypto inplace 1234 I get

logcat | grep crypt
E/Cryptfs ( 2407): Orig filesystem overlaps crypto footer region.  Cannot encrypt in place.


If I run vdc cryptfs enablecrypto wipe 1234 I get

device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table
device-mapper: table: 254:0: crypt: Error creating IV
device-mapper: ioctl: error adding target to table


and the device reboots afterwards...

Some extended information:
fstab

cat /fstab.boundary
....
$BD4    /data    ext4    nosuid,nodev,nodiratime,noatime,nomblk_io_submit,noauto_da_alloc,errors=panic    wait,encryptable=footer
....


init.rc 

cat /init.boundary.rc
...
mount_all /fstab.boundary
...


Screenshot from the partition layout:


Any help is very welcome.
I assume you use the wrong parameter in your fstab. You can't place the footer in space already reserved for a filesystem. Either make an extra partition (sdc5) and specify footer=/dev/sdc5:0 (to put it at the beginning of this partition) or specify a negative offset to use the space at the end of the partition, e.g. to use 16k of the partition specify: encryptable=footer,length=-16384

Not sure if you'd need to make your ext4 filesystem not smaller than the partition, otherwise it could overwrite your footer.