If you are comfortable with this process, could you tell me (e.g., A21s) you are trying to fix?
: This was the most common type of problem, occurring on Windows operating systems . In this case, the Windows USB driver would fail to properly recognize a device with an Exynos 3830 chip when it was connected in a special engineering mode, often called EUB (Exynos USB Boot) mode or Exynos mode. Repair technicians using specialized tools (like Chimera, Sigma, or Z3X boxes) would see the device but could not establish a proper communication link, showing a "yellow icon next to the Exynos port in the device manager" or receiving errors like "error(4.4.2.3) Waiting for EUB device... Device found, but cannot open" . This made it impossible to perform essential operations like FRP (Factory Reset Protection) bypassing , repairing the bootloader, or reflashing firmware. Driver Exynos 3830 Fixed
If the is not working on your machine, it usually stems from a driver signature issue, a corrupted driver, or an incompatible operating system version. Method 1: Proper Installation and Re-Enumeration If you are comfortable with this process, could
Use the button to navigate through the Android Recovery menu and highlight Wipe cache partition . Press the Power button to select it. Navigate to Yes and confirm with the Power button. Once the process completes, select Reboot system now . Step 2: Update Device Firmware (OTA) If the is not working on your machine,
(shorting specific pins on the motherboard while connecting USB) or the "Change to EUB" procedure in : If the device is stuck, use a Repair Boot