On January 7, singer/song-writer/composer Lim Han Byul dedicated a heartfelt letter to the members of X1, sharing both words of comfort and encouragements. Promoting as a solo artist, a member of Monday Kiz, as well as under the composer name Onestar, Lim Han Byul worked on X1's debut title track "Flash". 

He wrote, 

"After debating about it since yesterday, I'm leaving this letter carefully. I think I will regret it if I don't say these things now, as a hyung who watched the guys sweating through it all from nearby.

Who knew that the photo I kept stowed away for that day when I could use it to boast about you guys, would become a cherished memory so quickly. 

Who knew that those days laboring away in the recording studio on hands and feet, and your expressions of awe and shock performing at Gocheok would all become a faded past so fast. 

I'm sorry for not being more affectionate, at the time believing that I would be running into you guys more in the future. 

But I'm sure that you all will stand back up for sure, I mean someone like me still makes music even after all those bad downfalls. 

What faults do you guys have, when all you did was work hard.

Get back on your feet confidently and strongly, for the numerous fans cheering you on.

I will sincerely pray that you will all fly high above the mistakes of the adults with everyone watching. 

Let's meet again, you all did so well!"

Meanwhile, project group X1 will be disbanding after 4 months of promotions.