Actually, you can transfer your recordings from one disk to another. I just expanded my 1TB drive almost full, to a 4TB Drive.
I plugged the new drive into the Wally, and got it all set to go, with no recordings or timers on it.
I loaded VMWare Player 16 on my laptop, and loaded the Linux ISO for Ubuntu Version 20.04. When building the machine, I increased the VM disk size from 20GB to 50GB, to be sure to have enough room to transfer the files for the 25GB segment. Upon running the VM, I let it do the updates it asked for, then rebooted it. This is fairly important, as I faltered a few times, with bad information on how to get root access to the files on the disk.
There are two partitions on the Wally DVR, a small 25GB partition, and the remainder of the disk. The larger partition holds all the data for each recording or group of recordings in 3 files, es1.bm, es1.tsp, es1.wtt, where the video is in the .tsp file, judging from the size. My disk went up to es432.bm, tsp & wtt.
Mount both USB drives in your virtual machine. and copy all of the large partition files from the old drive to the new. Delete any files on the new drive before doing that. My 1TB disk took over 24 hours to do that.
Look into the 25GB partition, and copy all of your old JPEGs in the file folder 'persistent_graphics' from old to new, ignore any error messages, you should end up with the same images in the folder on both hard drives.
I did this one disk at a time, copied the folder contents into new folders in My Documents in the Virtual Machine, then swapped disks and copied the individual files into the folders already on the new larger disk. Linux didn't like copying the folders, so this last attempt I just picked out the files, and ignored any error messages.
Then locate the folder called 'databases', and copy the 5 database files from old drive to new, after deleting the new database files.
I was just guessing, but that was all it took to get the old recordings on the new drive.