Thank you for taking the time to post and welcome to the Bose Community. I'm pleased to hear your SoundLink Mini II has served you well thus far!
I'm sorry to hear you're encountering an issue regarding a flashing red LED now, however. I would've certainly recommended trying resets, and also visiting the BTU site HERE, to push any available firmware to the speaker. If you're having issues with the speaker being recognized, I'd recommend trying a different charging cable or using a different computer to push the firmware.
Once you're able to push the firmware update, you should notice an improvement to the speaker. If you still run into issues doing this, please let us know. Also, are you located within the US?
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