A thank you to nozorrog description for Amiko Spark DVB-T
Picon's name of terrestrial channel for Spark 2 has next format:
0_0_0_0_2B368_0_544.png
0_0_0 = TV channel
0_0_1 = Radio channel
_0_ (always 0 for dvb-t & dvb-c)
_2B368_ (frequency in hex, f.ex., 177000 for 177MHz)
_544 (SID in hex)
I backed up channels on Amiko 6 to USB drive then used eSettings software to read the file which gave me the frequency and SID, converted those from bin to hex and got it working.
Ifi t helps anyone else these are the correct names for Saorview channels in Ireland, the Amiko A6 does not auto download DVB-T picons, you need the png in 220x132 resolution as well.
RTE1HD = 0_0_0_0_79950_0_835.png
RTE2HD = 0_0_0_0_73B90_0_44E.png
TG4 = 0_0_0_0_73B90_0_450,png
RTEJR = 0_0_0_0_79950_0_83B.png
RTENEWS = 0_0_0_0_73B90_0_451.png
VIRGIN1 = 0_0_0_0_73B90_0_44F.png
VIRGIN2 = 0_0_0_0_73B90_0_452.png
VIRGN3 = 0_0_0_0_73B90_0_452.png
You will also need to fully reboot the box after the picon upload for the new icons to load in the DVB/EPG apps.