You encounter high CPU activity on a Surface Pro 2 device when a microSD card is inserted during boot

Symptoms

When you boot a Surface Pro 2 device that has a microSD card inserted, you may experience high CPU usage. The average CPU usage is about 20 percent when this issue occurs. This could lead to decreased battery life, poor application performance, and increased heat and fan activity on the device.

Cause

This problem is caused by a race condition in the device UEFI startup sequence, and this causes the microSD card to be stuck in a looping query. This looping query continues to consume CPU resources on the device indefinitely while in the problem state.

Resolution

To prevent this issue, install the updated UEFI package available at the following URL:

http://download.microsoft.com/download/5/7/A/57A4F5B1-FB4B-478A-B780-7A834B24C835/May 2014 Pro 2 FW.zipTo install this update, you must first boot the device into Windows. If your device is experiencing the problem described in the "Symptoms" section, you may have to restart multiple times in order to boot correctly into Windows. After you have booted into Windows, download the package from the previously mentioned link, or copy the file to the Surface device over the network connection or by using external USB media.

After the file is copied to the device, follow these steps:

1. Extract all files in the May 2014 Pro 2 FW.zip file to a folder on the hard disk of the device.

2. Open Device Manager (you can press the Windows logo key+X on the keyboard, or you can search for Device Manager by using the Start screen).

3. Select the Firmware node.

4. Right-click Surface Pro UEFI, and then select Update Driver Software….

5. Select Browse my computer for driver software, then Let me pick from a list…, and then select Have Disk.

6. In the extracted files, browse to \May 2014 Pro 2 FW\UEFI\2.04.0750\SurfaceProUEFI.infand select OK, Close, Next, and then Close. Do not restart when you are prompted.
   
   Note You can restart between each installation without causing any problems on the device. However, you should install both updates in order to make sure functionality of the Surface Pro 2 device is optimal.

7. Right-click Surface Pro Embedded Controller, and then select Update Driver Software….

8. Select Browse my computer for driver software, then select Let me pick from a list…, and then select Have Disk.

9. In the extracted files, browse to \May 2014 Pro 2 FW\EC\24.01.50\SurfaceProEC.infand press OK, Close, Next, and then Close.

10. Restart when you are prompted.

Note During restart (while the Surface logo is displayed) the message "Please wait while we install a system update" will be displayed briefly.