TP-Link C2600 drops connection every few seconds

Hei. I have a problem with LeDe and OpenWrt on C2600.
I just install new firmware, on both same issue
lede-17.01.4-ipq806x-C2600-squashfs-sysupgrade
lede-17.01.4-ipq806x-C2600-squashfs-sysupgrade

problem with connection during opkg update
Just drop connection with WAN
I checked ping and is look like that

C:\Users\Lenovo>ping onet.pl -t

Pinging onet.pl [213.180.141.140] with 32 bytes of data:
Reply from 213.180.141.140: bytes=32 time=76ms TTL=52
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=73ms TTL=52
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=73ms TTL=52
Reply from 213.180.141.140: bytes=32 time=73ms TTL=52
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=74ms TTL=52
Reply from 213.180.141.140: bytes=32 time=96ms TTL=52
Reply from 213.180.141.140: bytes=32 time=73ms TTL=52
Reply from 213.180.141.140: bytes=32 time=128ms TTL=52
Reply from 213.180.141.140: bytes=32 time=205ms TTL=52
Request timed out.
Request timed out.