Hello Friend !
I recommend the following update process:
1 - Backup the switch configuration file.
2 - Download the firmware "5500.EI-4800G_5.20.R2221P22" after update the bootroom file (btm) and binary (.bin);
3 - If the above process worked, download the firmware "5500.EI-4800G_5.20.R2221P25" and only update the binary.
Note.: Perform updating by CLI.