Mt7601u Can not work on tp703 tp720 with op18 and lede17

Installing and Using OpenWrt
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tp703n tp720n lede 17.06 .2 .3 .4 .5 .6
tp720n op18.06.1
After installing mt7601u, you can see the wifi signal 100% can scan and can join the network.But as wwan can not get ip.
Raspberry pie b+ has problem mt7601u and can only work under lede 17.06.2.

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Any solution Pleaaaase

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I'm having same problem, some of you were able to get it working?