GodMode9 gone crazy cannnot boot or run safe mode

Hi guys so i think I've really messed up.
i'm no CFW expert but i love to experiment. I've been running GM9 and Luma for a while (about 6 months) on my old 3ds. Now for some reason the 3ds boot is going crazy. if i pres the power button it goes to the GM9 menu - except that if i press any buttons it just cycles through the menus and i cannot input anything - sometimes the back-light goes and i cannot even see what i'm doing - the only command that work is R+START to shut it down.

I tries the L+R+Dpad UP+A to start into recovery mode and that booted it to the home screen but then if i try and open anything it crashes back to GM9 and the screen cycling continues.

I have a horrible feeling that the system updated recently - maybe thats messed up something in GM9 or LUMA?

thanks in advance for any advice you can give

 

So without the SD i get the same issue, but with an SD with just Boot.frim on it, it boots to Luma3DS configuration - however the system is unresponsive and is not accepting any input.

 

So i did this:

- get latest luma (v10.2.1, boot.firm - your SD card if it isn't already there
- get config.bin and place it in /luma/, replacing the old one if it exists - try to boot

it booted fine, went into the TWiLight menu++ - it loaded with a weirdly small screen - so i quit out to home and it went back to the Home menu - i did a reboot to test and its booting (slowly) bak to home so i think the main issue is fixed. now justy gotta work out why some software isnt working properly (for example FBI launcher wont boot and the TWiLight menu++ has the screen thing)

 

Amazing and thanks for all the help - at least i know what to try and fix now - i assume its a take the console apart job to fix?
EDIT: i have used some testing software and it does show the START button is permanently pressed

 

Thanks for all the help everyone - fixed the start button and the 3DS is running again as normal.