You might hold on just a minute.....
CWM isn't really intended to completely flash a NEW ROM to your device. Different custom ROM's have variations in parameters that tell the flash tool where the partitions go on the device. Because of that, you really need to flash custom ROM's from a PC. If the partitions already on your device are different sizes than the custom ROM, you could brick your device because things just can't overlap.
Manufacturers use the update.img from recovery...but they try to keep everything in standard partition sizes.
Here is an excerpt from a post I just made on one of my Pipo threads:
So, I think you would have better luck holding off on using CWM to flash new ROM's...and go get a USB cable. You will have much better results....if you can get the Rockchip Drivers installed properly, you'll be good to go.
CWM is really intended as a tool once you get into everyday use of your device. If things go really bad, you can use CWM to reflash the same ROM you had installed on your device.
You know how Windows has a recovery feature? You can use it to return to a stable state if you install an app that ends up jacking things up (like the wrong Rockchip drivers, hint, hint). Most people never have to use that feature of Windows.
CWM is kind of like that. The idea is to have a CWM backup on your system, so you can conveniently return to the last stable state (so it's a good idea to make a CWM backup before installing a potentially harmful app...or if you have everything perfect, the way you want it...make a backup).
Since us flashaholics have a mindset of "what to do to restore after flashing a new ROM", we look at CWM as a possible solution in that application, but it really isn't intended for that purpose. It has other features, though...like CWM app installation...and clearing cache and other cool stuff.
I keep an external SD in all of my tablets, and use Titanium Backup to keep a complete backup of apps/data. I keep the backup up to date with the current versions of each of my apps. After flashing a ROM, I immediately set up wifi, enter my Google account and go the Google Play Store to install Titanium. Then I tell Titanium that my backup is on my external SD and do a "restore missing apps with data" from Titanium, and within minutes my tablet is always back to everyday use....it takes about 10 minutes...(because the whole process is second nature to me, now).