Just like a CMOS reset ?
Never thought of that ^^
Edit : set up everything as should be for El Capitan =>> stuck on Apple logo screen, no progress bar.
I'll simulate install from USB stick to see if I can boot from there (I still have my El Capitan install stick).
Edit 2 : I tryed USB install following the guide with Clover 2.3 =>> stuck at 75% on progress bar on apple logo loading screen or I-don't-know-where in verbose
I updated my Clover to 2.4 (sad there is no link/thread here to find the last version easily or I'm dumb and didn't found it ^^) and Sierra install screen popped up
I was afraid to be in Murphy's thing : don't try to change/fix something working
Now installing on secondary HDD before updating my original one. Maybe just updating Clover on my El Capitan setup was just needed...
Edit 3 : After reboot from new installed system I tryed to go back to my El Capitan install : Worked !
Now I'm updating to Sierra...
Edit 4 : El Capitan updated to Sierra, Nvidia driver finding update by itself, minor softwares updates to do (Wacom driver...)
Edit 5 (last one ^^) : links to audio_CloverALC-xxx.comman.zip and Audio_CloverHDMI-xxx.command are brokent (on the first post). Here are the links for GitHub pages :
audio_CloverALC-xxx.comman.zip and
Audio_CloverHDMI-xxx.command.
On respective page, click on the download button on the right.
Works fine for me herr, got sound back.