Artefacts since last update

since the last osmc update I get picture artefacts.
Setup: osmc on RPi 3, TVHeadend
Before the update everything works fine.
What can I do?
How can I role back to prev. Version ?

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I fixed the problem:
I attached an Y cable to my external HDD so that it can get enough energy.
Dont know why this issue occurs since the last update but now everything is fine.