The update .img? is base firmware & firmware from the gui? bundled together.
Have you tried going back to V1.1.6. do that.? Where are you getting your firmware from.
Try ?? or ? https://www.radioddity.com/blogs/all/xiegu-x6100-firmware-upgrade?srsltid=AfmBOoonKJLsO_XIY0EXzFXHZlAgjoE5uXWqCWGr8601scXOQR7V-vyv
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The idea of removing battery power is to completely remove power? in case it hangs & can't control via power button.
You do want to do any upgrades with 13.8v psu connected as it recommends.
A bit more? make sure a good clean SD card with
Have had a problem with not doing that in the past. Also use Balena Etcher portable version
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