network – Change the routing priority on iMac

Our phone / Internet at home is down; dug up by the council contractors, and will not be fixed for a week.
I use an iPhone hotspot in the meantime.

It works, but when I connect the Ethernet connection to my router to my iMac, I can not access the Internet anymore.
I use the local network for file sharing and printing.

How can I prevent iMac from using the Ethernet connection for the Internet or PREFERABLY setting the priority so that the access point is higher when connected?

172.20.10.1 is the IP of the hotspot

~ $ netstat -nr
Routing tables

L & # 39; Internet:
Destination Gateway Flags Refs Use Netif Expires
default 10.1.1.1 UGSc 53 0 en0
default 172.20.10.1 UGScI 13 0 in1
10.1.1 / 24 link n ° 6 UCS 2 0 en0
10.1.1.1/32 link n ° 6 UCS 1 0 en0
10.1.1.1 78: a0: 51: 16: bb: 56 UHLWIir 31 156 en0 1192
10.1.1.9/32 link n ° 6 UCS 2 0 in0
10.1.1.255 ff: ff: ff: ff: ff: ff UHLWbI 0 1 en0
127 127.0.0.1 UCS 0 0 lo0
127.0.0.1 127.0.0.1 UH 1,300 lo0
169.254 link n ° 6 UCS 0 0 in0
169,254 link n ° 7 UCSI 0 0 in1
172.20.10 / 28 link # 7 UCS 1 0 in1
172.20.10.1/32 link n ° 7 UCS 1 0 in1
172.20.10.1 3rd: 2nd: f9: 2a: 33: 64 UHLWIir 15 12 en1 1181
172.20.10.5/32 link n ° 7 UCS 0 0 fr1
172.20.10.15 ff: ff: ff: ff: ff: ff UHLWbI 0 1 in1
224.0.0 / 4 link # 6 UmCS 2 0 en0
224.0.0 / 4 link # 7 UmCSI 2 0 in1
224.0.0.251 1: 0: 5e: 0: 0: fb UHmLWI 0 0 in0
224.0.0.251 1: 0: 5e: 0: 0: fb UHmLWI 0 0 in1
239.255.255.250 1: 0: 5e: 7f: ff: fa UHmLWI 0 10 en0
239.255.255.250 1: 0: 5e: 7f: ff: fa UHmLWI 0 10 in1
255.255.255.255/32 link n ° 6 UCS 1 0 en0
255.255.255.255 ff: ff: ff: ff: ff: ff UHLWbi 0 2 in0
255.255.255.255/32 link # 7 UCSI 0 0 in1