The NSDDW61 error is a warning sign, not always a death sentence. But given the low cost of new SD cards (as low as $0.10 per GB), why risk data loss? Repack, test thoroughly, and then relegate the card to low-stakes storage.
(removes NSDDW61 partition data): sudo dd if=/dev/zero of=/dev/sdb bs=1M count=1 nsddw61 sd card repack
Is your head unit showing a or a password unlock prompt ? The NSDDW61 error is a warning sign, not
A "repack" typically refers to a downloadable software image or a physical replacement card provided by third-party services. Because official Toyota dealers outside of Japan often cannot provide these legacy cards, many owners turn to specialized online vendors or forums to find "repacked" firmware files that can be written to a standard SD card using a PC. He clicked restore
He clicked restore. A folder appeared: . Inside, a single file: readme.txt . He opened it.
If your attempts at repacking are unsuccessful, your best options are purchasing from a reputable vendor like NavigationDiskJP, finding a used original card, or replacing the entire navigation unit with an aftermarket solution.
Let me know if you want a longer post, different wording, or to include the actual checksum and test logs.