@knc1: FWIW, my good old k2i holds charge much, much, much better than any of my newer devices, and it's the one seeing the most 'cupboard time'

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@chippychipchap: Ha! Thanks, that confirms what aditya & I though. It's too old to handle Kindlets, so, no KUAL, nothing you can do about it besides updating

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So, I'd say try to update it to 2.5.8, and check the logs (;dumpMessages in the searchbar) afterwards if it fails to pinpoint the offending files.