MicroSD Compatibility with Windows Phone 7

If you use a Samsung Focus WP7 device, then you have a “Consumer Accessible” MicroSD card slot into which you can plug a card of your chosing.

Unfortunately, your favorite brand may not be compatible with WP7 devices, but you wouldn’t know that because Microsoft has decided not to publish a list of Compatible cards at this time.  Since most of the WP7 devices do not have a Consumer Accessible slot, it was not deemed a high priority for apparently good reason.

Unfortunately, a lot of users were also trying to increase the amount of base memory of their units by replacing the built-in memory cards that the OEM installed in the (supposedly Consumer Inaccessible) cardslot.   When this strategy began to fail on a large scale for users, they began publishing their findings, which has created a new sense of urgency for Microsoft.  

Now a lot of consumers (myself included) are getting upset over this lack of  standardization by Microsoft.  I have burned thru two cards and found them to be incompatible.  Luckily they were newly purchased, so it was just a matter of returning them for a refund.  

My third try, a card from a no-name company called TopRam, turned out to be stable so far (knock on wood).

Another frustrating aspect of this testing is that it can take a while for the incompatibility of the MicroSD card to show-up.  From personal experience, I can say that I have found that the best test for compatibility is to simply restart your device (aka a “soft-reset”), either by pressing and holding your power button (the device should then say “Goodbye!”), or by pulling the battery out.   If all of your customizations disappear after the restart, then the microSD is not compatible.  I performed the soft-reset about 40+ times on the TopRam card, and it never struck-out, so I’m feeling fairly comfortable with it. 

I have also found that Class-4, as a speed classification, seems to be a requirement for compatibility more than anything else.   Oddly, a Class-10 card (a much higher access speed) failed to work, and the cards natively used by the OEMs are SanDisk Class-2 8GB cards, so obviously higher speed is not the most important consideration here.

If you’re going to try testing cards yourself, I recommend the following steps:

1.) Confirm that the retailer will accept any incompatible card back prior to purhcase.  
2.) You can then reformat the new card: 
– From an “off” state, press and hold the VOL-DWN button, the PHOTO button, and the POWER button. 
– Continue to hold even after the SAMSUNG logo appears on the screen to get to the Format Utility. 
– Press the Windows Logo button twice to confirm the requested action.
3.), Follow the Registration process on the device to the point where it tells you “you’re done!”.
4.) Then simple customize the Tiles a little bit, just so you can definitively tell whether things have changed.  If it’s going to fail, best not invest a ton of time customizing the device. 
5.) Then just do the soft-reset a few times and see if the customizations stick around…

Below is a list of cards from SanDisk of cards that were supposed to be compatible with WP7, but this list has since been withdrawn from their website: