[Transformer TF300T Q&A, Help & Troubleshooting] se242196sa:
Since I've had lots of problems, as I wanted to install Cyanogenmod 10.2 on my asus tf300t, I'll write down this guide to facilitate all those who wish to complete the procedure.

First, take into account that this procedure will INVALIDE the warranty of your device and my BRICK your device, so don't charge me for some errors which may occur; I trie it and it worked for me, but I don't feel responsible if something shouldn't work for you!!

What you need:

1) Asus transformer pad tf300t (not TG) with official android JellyBean 4.2.X loaded.

2) Unlock your bootloader.

The asus tf300t comes with the bootloader locked, so if you wish to unlock it download you have to download the official Unlocking apk file and run it on your device

(I used this one: http://blog.askseb.com/1567-unlocking-and-rooting-asus-transformer-tf300-with-android-4-2/)

once you have unlocked the bootloader

3) Install adb and fastboot on your pc

In ubuntu >=12.10 it is already installed;

Otherwise you can type in the terminal

sudo add-apt-repository ppa:nilarimogard/webupd8

sudo apt-get update

sudo apt-get install android-tools-adb android-tools-fastboot

4) Download CWM or TWRP

CWM didn't work for me, so I installed TWRP, which is even better then CWM;

I downloaded the 2.6.3.0 version it from here http://teamw.in/project/twrp2/97

5) Install TWRP

Now you have to install it, hence:

Turn of the device and turn it on in by pressing Vol- and Power, until you see three icons on the screen (RCK, Android, Wipe Data)

Now open a shell in your pc and type

fastboot -i 0x0b05 flash recovery /<...>/openrecovery-twrp-2.6.3.0-tf300t-4.2.blob

where <...> must be replaced with the path where you can find your file;

If everything worked properly, in no more then 10 sec, the process should be over and you should see a blu tab on the screen of the tablet, if so type in the terminal

fastboot -i 0x0b05 reboot

to restart your tablet.

6) Download Root zip folder from here

http://dottech.org/88787/how-to-root-asus-transformer-pad-tf300t-and-install-clockworkmod-recovery-guide/

and place it into an external sdcard

7) Download Cyanogenmod (I took 10.2 stable version) from here

http://download.cyanogenmod.org/?device=tf300t

and place it into the same external sdcard

8) OPTIONAL If you wish download also Google apps suitable for yuor cyanogenmod (I didn't do it) and place it into the same external sdcard

9) Switch off your device and turn it on as before by pressing Vol- and power;

Then move to RCK icon by using Vol- and select it pressing Vol+

After this you should enter TWRP;

10) Now make a backup copy of the system and if you want of your data (you will loose all of them!) and save into the external sd card

11) Now choose install from external sd card and choose the root zip

11) Then, always as you are in TWRP we have to wipe all your data;

12) and also wipe the cache partition

13) Now choose "install from external sd card" and choose your zip containing cyanogenmod, and also the one containing your gapps (if you have downloaded them).

14) Once it's over reboot your tablet and if everything worked properly, enjoy cyanogenmod!!