I have no hands-on experience with WD’s external hard drives, so everything I know, or think that I know, comes to me as feedback from end users or data recovery professionals. That said, some data recovery professionals have confirmed that certain external hard drives can be recovered by swapping the USB-SATA bridge board with an identical product of the same capacity. Others say that they have had to transfer the serial flash memory IC from the bridge board to the donor. This flash IC contains the program code for the Initio INIC-1607E bridge chip. It also stores the Vendor ID and Product ID for the WD device.
If your Initio bridge IC has an “E” suffix, then it incorporates 128-bit AES hardware encryption. This means that your data will be encrypted, whether or not you have set a password. A “P” suffix (INIC-1607P) denotes that the bridge does not have encryption. If you connect an encrypted drive directly to a SATA port on your motherboard, then your data will appear as jibberish, as you have already found out. You can confirm that the data are encrypted by using a disc editor to view sectors 0 and 1. Sector 1 will typically contain a repeating pattern of 16 bytes. These correspond to encrypted zeros.
The layout of the drive consists of a user area at the beginning. This is followed by approximately 600MB of unencrypted SmartWare software in the form of a virtual CD (VCD). This VCD uses a hybrid format (CDEveryWhere) that is mountable by Windows, Linux, and Mac OS. At the end of the drive is information required by the Initio bridge for its own use. The external drive is actually a multifunction device. When connected to a USB port, it first enumerates as an external optical drive (VCD), then as a USB mass storage device.
If the drive is installed behind the bridge, then only the user area is visible to the OS. The bridge hides the rest. If you compare the total number of LBAs reported by your software, it will be less than the total number printed on the drive’s label.
Here is a thread where a user has reverse engineered a HP SimpleSave external HDD:
The SimpleSave drive appears to be an OEM version of WD’s SmartWare. In fact the VCD code contains the name of a WD employee (Kathleen M.) who may be able to shine some light on how it all works.
To address your data recovery problem, ISTM that you will need to be lucky with your replacement bridge board. Morever, even if it is a perfect match, you will need to use TestDisk once more to restore the original partition table. However, before you do this, you will need to confirm that the user area of the disc is being correctly decrypted by the new board. To this end you could examine sector 63. This will be the boot sector of the first partition and should contain recognisable text strings, such as “NTFS” or “FAT32”.
Here are two free disc editors:
HxD - Freeware Hex Editor and Disk Editor:
DMDE (DM Disk Editor and Data Recovery Software):