We investigate the fractional Vasicek model described by the stochastic differential equation dXt=(α−βXt)dt+γdBHt, X0=x0, driven by the fractional Brownian motion BH with the known Hurst parameter H∈(1/2,1). We study the maximum likelihood estimators for unknown parameters α and β in the non-ergodic case (when β<0) for arbitrary x0∈R, generalizing the result of Tanaka, Xiao and Yu (2019) for particular x0=α/β, derive their asymptotic distributions and prove their asymptotic independence.