Here is the newest F/W for DSO :
DS0201_FW_V2.02_SS.rar (20 KB)
BTW, the D2 is a ESD protect diode, there are many model ESD diode of 5V , you can choose some similar parameter to replace it . and here is the datasheet of D2 :
CESD5V0AP.rar (290 KB)