This is a "fail-safe" mode. When the controller detects a NAND flash error, it locks the drive to prevent data loss, making it read-only.
The official utility for Phison-based Toshiba drives. vid 0930 pid 6544
Users searching for "VID 0930 PID 6544" often encounter one of three problems: the drive is write-protected, it shows "No Media," or it is not recognized at all. 1. The Drive is Write-Protected This is a "fail-safe" mode