1.- Enable ssh in DSM web UI
2.- ssh to our DSM (in Mac/linux - ssh user@dsm_ip, from windows putty or similar)
3.- cd /usr/syno/etc/packages
4.- sudo cp feeds feeds.old
5.- edit feeds with vi, nano or similar (remember sudo before nano feeds)
delete line
add text below
save & exit
text to add:
[{"feed":"http://packages.synocommunity.com/","name":"Synocommunity.com"},{"feed":"https://www.cphub.net","name":"https://www.cphub.net"},{"feed":"http://cytec.us/spk/","name":"http://cytec.us/spk/"},{"feed":"http://jaspr.kastner.wtf/","name":"http://jaspr.kastner.wtf/"},{"feed":"http://packages.jdel.org/","name":"http://packages.jdel.org/"},{"feed":"http://packages.page81.net/","name":"http://packages.page81.net/"},{"feed":"http://packages.pcloadletter.co.uk/","name":"http://packages.pcloadletter.co.uk/"},{"feed":"http://spk.diablos-netzwerk.de/","name":"http://spk.diablos-netzwerk.de/"},{"feed":"http://spk.naefmarco.ch/spkrepo/packages","name":"http://spk.naefmarco.ch/spkrepo/packages"},{"feed":"http://spk.nas-mirror.de/spkrepo/packages","name":"http://spk.nas-mirror.de/spkrepo/packages"},{"feed":"http://spk.synologyitalia.com/","name":"http://spk.synologyitalia.com/"},{"feed":"http://syno.dierkse.nl","name":"http://syno.dierkse.nl"},{"feed":"http://synology.acmenet.ru/","name":"http://synology.acmenet.ru/"},{"feed":"http://www.hildinger.us/sspks/","name":"http://www.hildinger.us/sspks/"},{"feed":"https://synology.cambier.org/","name":"https://synology.cambier.org/"},{"feed":"spk.unzureichende.info/","name":"spk.unzureichende.info/"},{"feed":"synology.sysco.ch","name":"synology.sysco.cht"},{"feed":"http://spk.netzbaer.de","name":"http://spk.netzbaer.de"},{"feed":"http://synorepo.tk","name":"http://synorepo.tk"},{"feed":"https://get.filebot.net/syno/","name":"https://get.filebot.net/syno/"},{"feed":"synology.nzbusenet.com","name":"synology.nzbusenet.com"}]
PS1: If you wanna edit the text, after feed add the address of the repo you want to add. After name, put the name of the repo added before. Remember insert a comma between repos and everything is in the same line. I think is easy to understand, if you have problems put your repo and I'll add it.