When I run the MDK-ARM Version 4.10 update (MDK410.exe), the content in ../Keil/ARM/RV31 is overwritten. I think it should be the ../Keil/ARM/RV40.
To fix this, I rename the overwritten RV31 to RV40 and copy back the RV31 from ../Keil/Backup.xxx.
This behaviour is also true for the previous 4.03a version (maybe for all 4.xx updates)