On the US keyboard, the back slash and vertical line, for some reason, have their own key. Since I write prose more than programs, I much preferred those keys to be brought up by an fn keystroke and in their place, I wanted a simple quote and double-quote key. I sacrificed the fn call of the Pound and Euro sign (apologies to my European friends) and replaced said keys with back slash and vertical line respectively.
To start me off, I found:
https://translate.google.com/translate?hl=e...amp;prev=searchand followed this fellow's instructions as best I could. For openers, you've got to download gbs of Android Studio and its plugins. So space beware.
Long story short: by extracting, then editing the keyboard kcm file (for your specific keyboard) from the /raw directory in "Gemini Keyboard 1.0.24.apk" (using 7-Zip File Manager), you can build a basic Hello World apk that will install a new keyboard layout (without overwriting any existing kcm) and you can choose that layout from Physical Keyboard settings. Make certain that your new, edited kcm has its own unique name, or an overwrite could happen.
I found this procedure to be both fascinating and a huge learning curve. If someone decides to be intrepid but gets stuck, I'm happy to email my 10mb source file for this apk (apk itself is 1.5mb). Theoretically, you should be able to drop your edited kcm file in my source's /raw directory, rebuild the source with Android Studio, and create a working apk that has your own keyboard remapping.
Changing certain keys is probably not of interest to most users, but for me, the fn-M to get a simple apostrophe was driving me to distraction. That, and I like to tweak keyboards.
Also theoretically, if you're root, you should be able to simply edit the specific kcm file (eg: keyboard_layout_english_us_intl_gemini.kcm) on the Gemini itself with no apk stuff. But my searches never turned up anything other than the generic kcms. Perhaps Gemini converts the kcm to an xml hidden somewhere, I just don't know.
At any rate, pm me if you want the source, and I take no responsibility for anything that ensues,
Jake