If you snag a brand new 27-inch 2020 model iMac, be sure it has the storage capacity you’re looking for.
According to technical documents, the 4TB and 8TB configurations the flash storage expansion board is attached to a connector on the logic board. However, the expansion board and connectors are not present in the 256GB, 512GB, 1TB, and 2TB configurations.
The documentation states that the flash storage and logic board are paired for hardware and encryption purposes. As such, data will be lost if the logic board needs to be replaced.
As always, back up regularly, be sure to use Time Machine or the backup service of your choice, and be careful with your data.
Stay tuned for additional details as they become available.
Via The Mac Observer and MacRumors