For those who frequently change rom , doing a Task29 is highly recommended. It takes less than 5 minutes only. As I often flash roms, I do notice a great difference. If you are testing a new rom you can now safely conclude any "lag" isues ( fresh rom before install 3rd party) attributed to the new rom
I prefer this simpler method of doing task29 and flashing new rom>
1. Bootloader mode ( with unit switched off, press vol down button and off key ) - you will see tricolor screen
2. Connect phone to PC - you will see "serial" mode on screen change to "usb"
3. Run the Tsk29 exe file
4. When complete , you will see a white sv=creen and phone will stop at there as there is no rom to boot
5. Disconnect phone, take out battery , go into bootloader mode again ( step 1 )
6. Connect phone to PC ( as step 2 )
7. Run the rom flash exe RUU file
6. After flash complete and phone completed booting - hard reset it again
You could skip step 5&6. At the end of step 4 just before it reboot press vol down key. No need to yank out the battery.