MPC 1000 Problem

I just got my mpc 1000 recently, and getting to kno it, yesterday i downloaded jj os2xl to play and today i wanna change back to jj os1, but when i turn it on the screen shows 'tap tempo power on - os2xl' then jump back to 3.12 and I couldnt install the jj os1, why is that happening?

when the mp is off hold tap tempo, turn on the power while still holding the tempo button, once finished booting up it will be switched

or you can find the .os file in your mem card from the load screen and select the .os file and press "do it" then when you reboot it will be on whatever OS you just loaded. Don't forget to hold erase down while booting up the new os for the first time. This will clear any preferences from the previous os.