Please upgrade in CLI:

1.upgrade FD1108S_V2.4.06_200728_X000.img file and then reboot

2.upgrade FD1108S_V2.4.06_200728_X000.img file again but don't reboot olt

3.upgrade FD1108S_FW_V2.4.06_201111_1736_X000.img file then reboot

command: 
epon# system update firmware xxx tftp-server x.x.x.x