GRB 230228A: OSN optical upper limit

Following the detection of GRB 230228A by Swift (Dichiara et al. GCN 33378), we triggered the 0.9m OSN telescope in Granada (Spain) starting on Feb. 28 at 19:34:03 UT (~13.7 hrs post burst). Ten images covering the burst error region were taken in the I-band. No optical afterglow is detected in the stacked image down to I=20.2 mag. These results are in agreement with the non-detection reported by Lim et al. (GCNC 33380), Lu et al. (GCNC 33381) and Belkin et al. (GCNC 33383). We thank the staff at OSN for their excellent support.