Hi,
I was changing the case of my Raspberry Pi 4 and I physically broke the SD card 
.
My system was configured to have the hassos-data partition on an external drive.
I reinstalled the system, but I couldn’t find a way to link the partition to the new system.
I looked for procedures, but they make the move and erase the existing data on disk.
PS: command ha os datadisk list return an empty list.
I don’t know how it works exactly.
I restored a backup (taken from my hassos-data ssd).
After restoring the partial backup I got all the historical data and configurations, but I was only using the SD.
Furthermore, the SSD disk was not recognized.
I restarted the Raspberry and now it is using the SSD disk. I didn’t run any commands. Probably it was enough to install HA on a new SD, connect the SSD disk via USB and reboot the system.