Coolsand (formerly Coolsand Technologies, later part of Spreadtrum / UNISOC after acquisition) was a fabless semiconductor company that produced low-cost, highly integrated baseband processors. Their chips (e.g., the C100, C200, C300, Q300 series) were widely used in feature phones, ultra-low-cost smartphones, and IoT modules—particularly in developing markets (India, Africa, Southeast Asia) from the late 2000s to mid-2010s.
These chips run a proprietary boot ROM protocol (often referred to as Coolsand Download Mode) requiring a specific USB driver for low-level flashing, IMEI repair, and factory reset via third-party tools like Miracle Box.
If the specific Coolsand driver refuses to install, many technicians use a universal trick. The Miracle Box "Loader" driver (bundled with the box) has a fallback mode: coolsand usb driver for miracle box
The Coolsand USB driver is a low-level kernel-mode driver (.inf + .sys on Windows) that enables Miracle Box to:
Important: You must disable Driver Signature Enforcement on Windows 8, 8.1, and 10 (64-bit) before installation, as these drivers are often unsigned. Coolsand (formerly Coolsand Technologies , later part of
Warning: Do not download random EXE files from unverified sources. Many so-called "Coolsand drivers" are malware or bundled with adware.
The safest way to obtain the driver:
File name to look for: spd_coolsand_usb2ser.inf or CSD_CDC.inf.