The latest firmware addresses low volume problems while using apps like Spotify mainly on Android 12 devices. This firmware will reset the the volume values and in most case will correct your low volume issue.
To Install the New Firmware:
1) Connect a pair of headphones to the BOLT, and insert the BOLT into a USB port on your PC.
2) Launch the BOLT MQA Firmware Upgrade utility exe.
3) On the right of the "Source file info" field is a "Browse" button. Click "Browse" and find the "cust014ext_Helm_3osc_THD_0dB.ROM" file and select it so it appears as a directory listed item in the Source File Info field.
4) In the "Target Device Info" field "HELM USB-DAC" should be visible. If it doesn't appear, disconnect the headphones and reconnect and see if it shows up.
5) Click the "Burn" button. Once it completes the firmware update you can click "Verify" but it's not necessary.
If the new firmware "Loudest" 0dB ROM file doesn't remedy the low volume issue feel free to restore the original FW (Helm Audio Bolt Firmware (ver 7860) new) found in link above.
This Video Walks Through How To Perform the Firmware Update: Click Here