Tienes que hacer lo que pone en este post:
I just wanted to have a little post for those of you like me that may have tried updating after downloading the .28 OTA update, then the Prime freezing on the Asus Splash Screen and not rebooting...I found the solution after finally downloading the update this morning from Asus' TW site.
I only have the Prime as my computer and I have an Android phone. No PC for me - was going to try to use a friends last night to get into ADB but it just wasn't happening.
So for me - this is what I had to do.
If after your prime reboots you are still stuck on your asus splash screen, and nothing will get it to boot up - do this:
You must know your Prime's version of the update.
Goto
ftp://ftp.asus.com.tw/pub/ASUS/EeePAD/TF201 or check cky2000's thread right here
http://forum.xda-developers.com/show....php?t=1429873
Download the **COMPATIBLE** update of .28 (I tried .21 plenty of times - .21 would not update my Prime)
If on an Android phone (like I was) goto ES File Explorer and open the **UpdateLauncher.zip file
It should say something like **_epad-user.9.4.2.28.zip
Extract the file to the root directory of your microSD card
Now, goto your microSD card
rename the **_epad-user.9.4.2.28.zip to
EP201_SDUPDATE
**don't rewrite the extension so that it's EP201_SDUPDATE.zip.zip, ES File explorer will only allow you to rename the name, not file extension**
You should now have EP201_SDUPDATE.zip on your microsd
**make sure you charged your prime at least 30 min if it turned off previously**
Put microsd in your Prime
Hold the Volume Down button and the Power Button until it resets and something is written at the top asking if you want to boot into a certain mode press volume up.
Immediately press Volume Up. Make sure Microsd with EP201_UPDATE.zip is in Prime.
It will start to switch to the Android Operating Mode screen with the Android lying sideways with some nuclear fission animation going on.
Blue status bar should start within 3 minutes.
Reboot and rewrite should take approximately 5-10 minutes. When done, your About should show .28 update. Hope this helps anyone who was in the same boat as me. I believe my Prime was bricked a certain way - not sure how.
Sigue todos los pasos porque la gente dice que se recupera......
En resumidas cuentas dice que tienes que descargar la versión .28 correspondiente a tu prime, es decir la .28 WW si es de aquí, ponerla en la raiz de tu microsd renombrandola a "EP201_UPDATE" sin las comillas y con extensión .zip
A continuacion pulsas volumen- y el boton power a la vez asta que salgan unas letras que te preguntaran si quieres entrar en cierto modo, pulsas volumen+, después otra vez volumen+ y empezara a flashear el firmware de nuevo. Espera que termine, se reiniciara y se supone que se habrá arreglado....
Salu2