I have a XiaoMi 1. I don't think it's a M1S. Not sure how to tell. The system was on 2.3.5i. I could not update from within the settings. I followed the tutorials on these links: http://xiaomi.eu/community/threads/xiaomi-guide-to-install-update-zip-and-brush-tool.17241/ http://www.miui.com/thread-740315-1-1.html I can read some of the Chinese. I used the Chinese site to download the v4 ROMs. It should be in the first 3 links. I chose the 2nd link, stable version of v4. I tried updating through the Recovery using update.zip. It was ok wiping all data, installing update.zip. Rebooting to system one would end me up back into Recovery. I then tried using the Fastboot method. My Fastboot screen did not look like the ones that were on the 2 links I posted above. It had the bunny with the android robot but on the top it had "Power up reason USBCHG. Enter Fastboot reason KEY PRESS." I kept getting errors during the flash. Error saying Unspecified Error... size too large. I remember having my Windows 7 drivers not installed properly when I went into Fastboot. Could that be the problem? Also where on xiaomi.eu can I find v4 roms for XiaoMi 1? Thank you.