You can try and run the following commands (substitute rbp2 for rbp1 if necessary):
sudo systemctl stop mediacenter
wget http://download.osmc.tv/installers/diskimages/OSMC_TGT_rbp2_20160910.img.gz -O- | gunzip -c | sudo dd if=/dev/mmcblk0 bs=1M conv=fdatasync
Once this is done, power cycle the device.