As for where to download: Go to Xiaomi Forum to find this post: "Xiaomi mobile phone firmware updates MIUIv4 every 20 12 * * * weeks", select "Download new version", then select the MIUI version you want to download, and select the card brush package around 170M (MIUI2.3 must use a line brush).

The method of swiping the card is on this page: "Detailed explanation of playing Xiaomi mobile phone brushing tutorial". The fifth method used in this post is to swipe your card.

Note: The above is the brush package of Xiaomi mobile phone.

If you are another model, please go to MIUI forum to download the corresponding brush package.