I had the same question except for a Craig Tablet and all I have found for it are modified CWM for rk2918. one by androtab.info and another by Oma. maybe you can search for those. I am not sure how all this works but I think the "RKAndroidTool" will also be helpful here. in one case I could use update.zip and didnt need the RK tool. sorry I cant be of more help.
