I wrote up an EHD event transfer procedure for my VIP 211 years ago, but I have no experience with the Wally platform. The process is straightforward but can take some time depending on the number of event on your EHD. Fortunately, USB 3 drives speeds up the copying process.
If you don’t have a Linux PC, that’s okay as you can download a Linux .ISO file, boot to that, and do the disk-to-disk file copies using the Evaluation mode which runs as Linux root access.
You take the new EHD (the Target), plug it into your Wally, and let the Wally format the EHD. After that finishes, you plug it and the original EHD into the Linux PC. This is where I know nothing. What you might see is several partitions on the Source EHD with files in the drive‘s root folder with a number of randomly named folders; if Dish is consistent then those folders contain the recorded events.
Going partition by partition, you select all the files and folders from the Source EHD and drag them to the partition on the Target EHD. When you are finished, you dismount or eject the mounted partitions on the Target EHD so you unplug it from the Linux PC and reconnect it to the Wally. If it works like the VIP 211 family, you should be able to see all your programs, play them back, and notice all the available space on your new EHD.
The good thing about this process is your Source EHD doesn’t change, so you still have all your original Events.
Now, if this isn’t the process, hopefully someone with a Wally and EHD will be able to share the correct procedure.
edit: and from the link posted by
llokey the maximum EHD supported by the Wally is 4 TB (or at least it was in September 2021). Also, SSD is strongly discouraged based on the constant disk writing that’s being done by the Wally.