Over the weekend, reports surfaced that Microsoft's Windows Phone 7 OS will make permanent changes to an inserted microSD card, possibly preventing it from being read, written to, or formatted for use on another device.
The news arrives after AT&T recently told customers not to install extra microSD cards in their brand new Samsung Focus. Microsoft's own WP7 support docs also point out that the microSD card slot isn't meant for consumers to insert whatever they buy, but is intended to be used by the OEM that built the device and the wireless carrier that sells it.
"Determining whether an SD card is Windows Phone 7 compliant is not a simple matter of judging its speed class," the document reads. "Several other factors, such as the number of random read/write operations per second, play a role in determining how well an SD card performs with Windows Phone 7 devices."
However reports indicate that consumers are buying microSD cards anyway and are experiencing severe problems with the Samsung Focus, reducing performance to a crawl. AT&T stresses that only "Certified for Windows Phone 7" cards should be used if customers are intent on expanding the device's storage capacity. The problem is they’re not available for the general consumer.
"Windows Phone 7 requires a certified high-speed microSD card for optimal performance," AT&T said in a statement. "Because the Samsung Focus is expandable via a microSD card, only microSD memory cards certified for Windows Phone 7 should be used. This information is not currently marked on any microSD packaging in market today. As a result, we are advising customers to delay purchasing an external microSD card until the cards identified as 'Certified for Windows Phone 7' are available commercially or in AT&T stores."
Samsung also added in its Focus documentation that any card inserted into the device "will no longer be readable or writable on any other devices such as computers, cameras, printers, and so on." Engadget backs up Samsung's documentation, reporting that a microSD card was "fried" after moving it in and back out of the Samsung phone.
Later reports say that Microsoft is looking to certify microSD cards, however the only ones that play nice with Windows Phone 7 are only sold in bulk. Samsung claims that the 8 GB class 2 memory card should work just fine.
"The Samsung Focus has a 16 GB internal memory and expandable up to 32 GB," the company said. "So you can insert a 32 GB micro SD card on this device. Use of unapproved cards may cause performance degradation or device instability, including unexpected reset and loss of user data."