wget http://palosaari.fi/linux/v4l-dvb/firmware/Si2168/Si2168-B40/4.0.25/dvb-demod-si2168-b40-01.fw
dmesg
...
[   35.605149] si2168 5-0064: downloading firmware from file 'dvb-demod-si2168-b40-01.fw'
[   36.824341] si2168 5-0064: firmware version: B 4.0.25
[   36.843449] si2157 8-0060: found a 'Silicon Labs Si2157-A30'
[   36.898574] si2157 8-0060: firmware version: 3.0.5
[   36.943588] si2168 5-0064: downloading firmware from file 'dvb-demod-si2168-b40-01.fw'
[   36.951864] si2168 7-0067: downloading firmware from file 'dvb-demod-si2168-b40-01.fw'
[   38.081222] si2168 5-0064: firmware version: B 4.0.25
[   38.090572] si2157 8-0060: found a 'Silicon Labs Si2157-A30'
[   38.092594] si2168 7-0067: firmware version: B 4.0.25
[   38.101348] si2157 9-0063: found a 'Silicon Labs Si2157-A30'
[   38.115615] si2157 8-0060: firmware version: 3.0.5
[   38.151070] si2157 9-0063: firmware version: 3.0.5
[   38.172695] si2168 7-0067: downloading firmware from file 'dvb-demod-si2168-b40-01.fw'
[   39.367599] si2168 7-0067: firmware version: B 4.0.25
[   39.380975] si2157 9-0063: found a 'Silicon Labs Si2157-A30'
[   39.406462] si2157 9-0063: firmware version: 3.0.5