Here are teh steps to resolve the blank keyboard issue
-> Start your box as normal.
-> Go into Kodi (XBMC Media Center or DBMC if you are using these apps instead of Kodi)
-> From the main menu of Kodi, go into just SYSTEM then Appearance
-> Select Skin and hit OK
-> From the list select basic Confluence Skin
-> Its going to ask if you want to keep this change press Yes
-> Now go back into main menu of Kodi and you will see basic skin.
-> You will be wondering where all the Add-ons went, just go into VIDEOS then Add-ons and there you will find all the Add-ons that you had under other skins. Also if you try use keyboard in Kodi now you will see it with all the keys in it.
-> Usually the keyboard problem becomes a pain when a user wants to add something to Kodi and he is unable to type it because the keyboard is blank. So once keyboard is back you can add whatever you want and once that is done. You can switch back the good looking that you were on already you just need to follow the above steps and select the skin you want.