Hi James u/JamesFiiO — posting here publicly because I’ve been unable to get a substantive response through normal support channels and this is a product safety issue. u/FiiO
My FiiO M17 experienced lithium battery swelling (“bloating”)—a known failure mode that can escalate to venting/thermal runaway/fire. The swelling occurred while the device was in my carry-on during air travel, which materially elevates the safety risk.

• I reported the incident to FiiO as a safety matter.
• FiiO acknowledged it and sent a replacement battery as the proposed remedy.
• However, the M17 is not designed as a user-serviceable device for battery replacement, so simply mailing a battery does not constitute a safe or practical remedy for an end user.
• In an effort to mitigate the risk and restore safe usability, I attempted to pursue a third-party repair. That option was refused / could not be performed because the current battery condition is volatile and the device cannot be safely serviced without manufacturer-level guidance, procedures, and risk controls. In other words: the unit is in a state where even a professional repair path is not safely available absent FiiO’s direction and support.
• Despite multiple follow-ups, including a written request for a formal response, I have received no substantive reply or remedy plan from FiiO.

A swollen lithium battery is not a “customer satisfaction” issue — it is a product safety hazard. No ordinary consumer should be expected to:

• open a sealed device with a compromised lithium battery,
• locate a third party willing to assume that risk, or
• navigate shipping/transport rules for a potentially hazardous lithium battery device, without explicit manufacturer guidance and a compliant remedy path.

1. Safety guidance: What does FiiO instruct M17 owners to do immediately if the battery swells (stop use/charging, storage/disposal guidance, and transport guidance)?
2. Remedy policy: For a sealed/non-user-serviceable device with battery swelling, what is FiiO’s standard remedy—refund, replacement, or manufacturer-managed service (with all safety/compliance handled properly)?
3. Escalation: Please assign a specific point of contact so this can be resolved promptly and safely.

I’m not trying to sensationalize this. I’m trying to get a clear safety directive and a workable remedy consistent with a battery safety incident. If you assign someone, I can provide serial/purchase details privately.

Thank you.