If you own a Sony Xperia device—or an older Sony Ericsson device—and are trying to mod it, flash a custom ROM, or unlock the bootloader, you have likely encountered a device in Device Manager listed as "S1Boot Fastboot" or "S1Boot Download Mode."
Without the correct driver, this device will sit under "Other Devices" with a yellow exclamation mark, preventing your computer from communicating with the phone. This guide covers what the driver is and how to install it.
The s1boot fastboot driver is a platform-specific USB driver that enables communication between a host PC and devices that expose a fastboot-like bootloader interface under the "s1boot" protocol. It’s commonly used for flashing firmware, unlocking bootloaders, recovery operations, and low-level device management on certain SoC families and embedded devices that do not use the standard Android fastboot implementation. s1boot fastboot driver
Most Sony users use a tool called Flashtool (developed by Androxyde). When you install this program, it includes a dedicated driver installer.
Installing the s1boot driver often requires more than just running an executable. Below are the standard methods for installation. If you own a Sony Xperia device—or an
If you have the driver files (often found inside the Flashtool folder mentioned above or in a dedicated SDK download) but the automatic installer failed, do this:
s1boot is Sony’s proprietary low-level bootloader interface used on Xperia devices (and older Sony Ericsson models). When you boot the phone into fastboot mode (typically by pressing Volume Up while connecting USB), the device identifies itself with the USB VID/PID combination that Windows recognizes as “s1boot fastboot.” Select Devices:
If Flashtool failed, or you want to do it manually:
s1boot.inf file.