For some reason that is not relevant, i made a factory reset on my rooted ouya console. When i finished the set-up, the system installed Chupacabra R1 (1.2.1084_r1).
When i try to install "Root My Ouya" from sdcard using FilePwn app, i got "App Not Installed" as result.
NOTE: I don't remember if i had 1.2.995_r1 installed before factory reset (again, when i had root).
UPDATE: I did another factory reset. Ouya is now rooted.