UPnP/DLNA Bridge Plugin - FLAC issue

I'm trying to get the UPnP/DLNA Bridge plugin to stream FLAC files to a Yamaha CD-N301.

I've no issue playing FLAC files from the device itself (via minidlna) but the UPnP/DLNA Bridge plugin will only work if the FLAC files are transcoded to e.g. MP3.

With the following settings

<mode>flac</mode>
<codecs>flc</codecs>
<forced_mimetypes>audio/flac</forced_mimetypes>

I get the error

Slim::Player::Song::open (410) Error: Couldn't create command line for flc playback for

reported in the server.log whenever I try to play a FLAC file.

I have no issue playing same FLAC files to a Squeezebox Touch or a Chromecast via the Castbridge plugin using the same LMS install - only the UPnP/DLNA Bridge plugin reports this error.

If I add mp3 as a valid codec e.g.

<mode>flac</mode>
<codecs>flc,mp3</codecs>
<forced_mimetypes>audio/flac</forced_mimetypes>

Then I can stream via the UPnP/DLNA Bridge plugin - but the files are converted to MP3 in order to play them e.g.

Bitrate: 2807kbps VBR (Converted to 320kbps MP3)

Does anyone know why the UPnP/DLNA Bridge plugin seems to have a problem with FLAC files ?

I've also tried with

<mode>thru</mode>

but that behaves the same way as

<mode>flac</mode>

The only way to get them to play is to use MP3

<codecs>flc,mp3</codecs>