Hello justinline Welcome to the community!
This is a rather complicated operation to do, especially if you want a safe transfer of all data, settings and the installation itself.
It is recommended, for data safety, to do a fresh installation with Berryboot, but since you don’t want to go through this here are some tips on how you can proceed:
- Make sure the power supply can easily deliver enough power to both the Pi and the external drive in all cases so you don’t encounter shut-downs in case the Pi hits 100% load.
Verify the partition size that you want to transfer by using:
fdisk -l your partition
Make sure that all partitions are unmounted. Create an empty partition that is big enough on your WD PiDrive then move the system disk by using:
dd bs=4M conv=noerror if=your initial partition of=created partition on the WD PiDrive
Use gparted to correct any disk errors from te original SD card partition and then resize the partition to fit its new size with resize2fs. Mind that every disk UUID must be unique and you must set a new UUID. Once done simply quit the gparted utility.
Getting the new UUID can be done as follows:
Assign a new partition name by using e2label partition in the WD PiDrive partition name
Then obtain the new UUID by using this example:
partition on the WD PiDrive: UUID=“11ed1dc5-0507-48f1-b1c6-d5926df1ee88” TYPE=“ext4” LABEL=“name of the new partition name”
You need to prepare the new mount command:
Old SD Card partition / ext4 defaults,noatime 0 1
New UUID / ext4 defaults 0 1
Now you need to set a new root device:
[before] dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=old SD card partition rootfstype=ext4 elevator=deadline rootwait
[after] dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=New WD PiDrive partition rootfstype=ext4 elevator=deadline rootwait
You should be good and should be able to reboot by using reboot or shutdown -r now
You could also check this guide.
Again, mind that his involves a high risk of data corruption and damage to the file system and the partitions so it is recommended to simply do a fresh install and use the Berryboot.
Hope this works! Feel free to ask any questions you may have.