dammit beat me to the punch,again! i was just gonna say that. i used my refurb for 4 days,then went back to my original on the last day,and ended up sending the refurb back.
i did call them and explain that it had started workin again,what did they want me to do... and they said it was fine to send back the refurb.
my gut feeling says if you were looping in recovery and into the OS repeatedly that you were experienceing the emmc failure,and despite the fact that its somehow working,its prolly a matter of time before it happens again.
but who knows,lol... you may keep it and it be fine forever while the refurb craps out in a week.
its a tough choice. potential brick or crappy refurb... i feel for you man,ive been there
so just to satisfy my own curiousity... you put the phone in fastboot,started the installer,followed the prompts,the installer put the phone in ruu mode,and went thru its whole speal of flashing? im glad you did it that way,its good info to have that apparently "RUU mode" is not affected by the failing/failed emmc