Introduction
In some cases, such as when creating a Linux SD card for an Altera® (Intel®) SoC FPGA device, a boot SD card is used in Windows® 10 environment. The following may occur in Windows® 10 when a partition (volume) other than FAT is present on the SD card.
- A warning window appears when inserting the card.
- Failure to write the SD card image
This article describes the phenomena that may occur when handling a Linux boot SD card in Windows 10 environment and how to deal with them.
1. (Supplemental) Warning displayed when SD card is inserted
In Windows 10, if a primary partition (volume) other than FAT exists on the SD card, when the SD card is inserted into the PC, the warning "・・・ you need to format" is displayed as shown in Figure 1-1.
The warnings are for non-FAT partitions that cannot be handled by Windows, so basically ignore the warnings.
In this case, click Cancel on each warning window to close the window.
Figure 1-1. Drive Formatting Warning
You may also receive a warning about accessing the drive, as shown in Figure 1-2.
In this case, click OK in each warning window to close the window.
Figure 1-2. Drive Access Warning
If you check the USB Device Removal menu in the taskbar, you should see multiple drives assigned as SD cards, as shown in Figure 1-3.
Figure 1-3. Confirmation of drive assignment as SD card
2. SD Card Image Write Failure Phenomenon and Countermeasures
2-1. Phenomenon
To write an image file to the SD card, use a writing tool (in this explanation, Win32DiskImager is used).
Reference: Win32DiskImager
When writing with Win32DiskImager, the following error message may appear and the writing may fail.
Figure 2-1. Error display example when writing using Win32DiskImager
2-2. Countermeasures
The cause is the existence of a partition (volume) other than FAT.
Delete the two primary partitions (volume D and E in this explanation) from the SD card, except for the FAT partition (volume F in this explanation).
(1) Click "Start" from the Windows 10 Start icon.
From the Windows 10 Start icon, select "Control Panel" → "Administrative Tools" → "Computer Management" → "Storage" → "Disk Management".
Figure 2-2. Open "Disk Management" in Windows 10.
2) Click "Disk Management.
As shown in Figure 2-3 below, the disk allocation will be displayed, so check "Removable" for the SD card.
In addition to FAT (in this example, Volume F), there are two primary partitions (in this example, 3.32 GB and 10 MB).
Figure 2-3: SD card (removable media) allocation example
(3) Delete primary partitions other than FAT
Right-click on the two primary partitions other than FAT (in this example, 3.32 GB and 10 MB) and select "Delete Volume (D)..." to delete them.
Figure 2-4. Deleting two primary partitions other than FAT
If you check the drive after deleting the non-FAT primary partitions, you should see only the FAT partition on the SD card (in this example, Volume F), as shown in the following example.
Figure 2-5. View of the drive after deleting the non-FAT primary partition
(4) Writing SD card image
In this state, write the image file using a writing tool (in this example, Win32DiskImager is used).
Figure 2-6. Successful display when writing using Win32DiskImager.
(5) Ignoring warning messages
If a partition other than FAT is created in the SD card after successful writing to the SD card, the warning message "...formatting is required" will appear again.
In this case, click "Cancel" on each warning window to close the window.
(6) Using SD Card Formatter Tool
If you are still unable to write to the SD card after following the above steps, download and install an SD card formatting tool (SD Card Formatter is used in this explanation), format the SD card, and then try writing to it again.
Reference: SD Card Formatter
Figure 2-7. Example of SD card formatting using SD Card Formatter