You must load firmware R252B46_Sequential_Update before loading firmware R282B16.
However, if the firmware in your switch is newer then 2.52B46, then you can load firmware R282B16 directly.

To load firmware 2.82B16, please use below new CLI command:

download firmware fromTFTP <IPaddress> scr_file <path_filename>

<IPaddress> is the IPaddress of PC running TPTP program
<path_filename> is path where the firmware file is located on the PC. Usually same folder as TFTP program.

For example:

download firmware_fromTFTP 10.53.13.201 scr_file c:\DGS-3600_R282B16.had

