Hi all,
for a Sound-Project with an ESP8266 I had converterd an existing Javscript-Page.
Unzip it locally and start it. It provides a very basic gui to upload an file and it converts it into a HEX-File.
I have used it well to convert WAV-Files (16 Bit / Mono).
You have to wait a while till the converting-process has done its job. Then grab the content of the bigger Textarea and copy/paste it to Your Codeeditor.

Not a big thing but it works and could be something for another developer.

hex2h.html.zip

Best Regards
Erich