FiiO K19 Firmware V165: Update and Settings Guide
, by EMiUZEK Editorial Team, 6 min reading time
What FiiO K19 firmware V165 changes, how to update safely, configure the remote FN key, and recheck gain, outputs, HDMI, USB and PEQ settings.
FiiO K19 firmware V165 is a worthwhile update mainly because it improves control convenience rather than changing the K19’s core DAC or amplifier hardware. FiiO’s confirmed headline addition is customization for the remote control’s FN button. Owners should update only through the official FiiO package and instructions, preserve a stable power connection, and verify their settings afterward. If the K19 already performs reliably and the new shortcut is irrelevant, there is no need to expect a sound-quality transformation.
What V165 changes
The official V165 announcement focuses on a user-assignable FN key for the supplied remote. This is a workflow feature: it can reduce menu navigation for a function an owner uses often. It does not replace the K19’s dual ES9039SPRO DACs, eight-channel THX AAA 788+ amplifier, 31-band PEQ, HDMI interfaces, or input and output architecture.
Firmware notes should be read narrowly. Unless FiiO explicitly documents another change, do not assume V165 increases output power, alters the DAC filter response, adds network streaming, or changes Bluetooth codec support. Subjective impressions after an update are not proof of an engineering change.
Should you update immediately?
Update if you use the remote frequently, want the FN shortcut, or FiiO support directs you to V165 for your unit. You can wait if the K19 is part of a stable production or measurement system and you do not need the new function. Waiting allows time to confirm that your exact workflow and connected devices remain unchanged.
Before any update, photograph important menu pages or record PEQ presets and output settings. The most important items are gain, maximum-volume limits, PO/PRE/LO mode, USB Audio Class mode, HDMI behavior, and any imported equalization curves.
Safe firmware-update procedure
- Confirm that the package is specifically for FiiO K19 and MCU version V165.
- Download it from FiiO’s official support or news page, not from a reposted archive.
- Read the included instructions completely before connecting media or starting the process.
- Use stable AC power. Do not switch the rear power selector, disconnect the cable, or power off during the update.
- Disconnect unnecessary sources if the instructions recommend it, while keeping the required update connection in place.
- Wait for the K19 to report completion and restart normally before touching controls.
- Open the system information page and confirm that the displayed MCU version is V165.
If the displayed version does not change, do not repeatedly power-cycle the unit. Recheck the file, media formatting, folder placement, and official procedure. Contact support if the unit becomes unresponsive.
How to configure the new FN shortcut
After confirming V165, open the K19 system or remote-control settings and locate the FN-key assignment. Menu wording may differ by language or companion-app version, so follow the current on-screen label. Choose a function that genuinely saves steps, then test it at a low listening level.
Useful assignments depend on the system. Headphone users may prioritize gain or output mode. A desktop system may benefit from input switching. A speaker system may prioritize PRE/LO selection, but this requires special care because LO is fixed level.
Critical K19 settings to recheck
| Setting | What to verify | Why it matters |
|---|---|---|
| Gain | Start with Low Gain | The K19 can deliver very high headphone power |
| Output mode | PO, PRE, LO, or PO+PRE | LO is fixed level; PRE is volume controlled |
| Volume limit | Restore a safe maximum | Protects hearing and sensitive earphones |
| USB mode | UAC2.0 for computers; UAC1.0 when required | Determines source compatibility |
| HDMI ARC | TV set to compatible stereo PCM | K19 is not a multichannel Dolby/DTS decoder |
| PEQ | Preset loaded and enabled as intended | Prevents an unnoticed tonal or level change |
FN shortcuts that require extra care
Never assign a shortcut that can unexpectedly switch to a dangerous output state without understanding its behavior. LO sends fixed-level audio through the rear RCA or XLR outputs. If those outputs feed active speakers or a power amplifier directly, switching from PRE to LO can create a large volume jump. Reduce the downstream volume before testing and use PRE when the K19 should control listening level.
Gain changes also deserve caution. The balanced 4.4mm and XLR4 outputs are specified for up to 8000mW + 8000mW at 32 ohms in Ultra High Gain under FiiO’s test conditions. Sensitive IEMs rarely need that capability. Low Gain and a conservative maximum-volume limit are the safer default.
What the update does not change
The K19 remains a two-channel DAC, headphone amplifier, and preamplifier. It cannot directly drive passive speakers. Its rear analog connectors are outputs, not analog inputs. HDMI ARC accepts compatible stereo PCM and should not be treated as eARC multichannel decoding. Network streaming is not built in; add a streamer through a digital input if that workflow is required.
Bluetooth 5.1 reception and the supported codec set still depend on the transmitting device as well as the K19. USB decoding capability also depends on the host, driver, player, and file. A firmware update cannot make an unsupported source format or operating system behave as though it were officially supported.
Troubleshooting after V165
If there is no sound, first verify the selected input and output mode. PO activates the front headphone outputs; PRE and LO route the rear analog outputs; PO+PRE activates both adjustable paths. For HDMI ARC, confirm that ARC is enabled on the television and that the TV outputs stereo PCM.
If Windows no longer behaves as expected, confirm the selected USB Audio Class mode and reinstall the current official FiiO driver if necessary. For consoles, UAC1.0 may be required. If a PEQ preset appears ineffective, verify that the current input, sample rate, and format support that processing path; native DSD may bypass the same PCM equalization route.
Is the K19 still the right product after this update?
V165 improves convenience, but it should not be the main reason to buy the K19. The K19 makes sense for buyers who need very high balanced headphone power, detailed PEQ, HDMI and HDMI ARC connectivity, flexible fixed or variable rear outputs, and a compact flagship desktop format.
It is excessive for easy-to-drive headphones when a simpler DAC/amp already provides clean power. It is also the wrong choice if you require analog input, built-in network streaming, or direct passive-speaker output. Features, compatibility, and system architecture should lead the decision.
Bottom line
Install K19 V165 for the customizable remote FN key and any official fixes listed for your package, not for an assumed sonic upgrade. Back up settings, use stable power, confirm the version, and recheck gain, volume limits, output mode, HDMI, USB, and PEQ before normal listening. The FiiO K19 product page at EMiUZEK shows current regional options and inventory. For adjacent setup decisions, see our FiiO K15 and K17 comparison, K11 R2R DSD settings guide, and DAC headroom explainer.