Saturday in Belgium and the sun is shining.
I managed to install OSX by using target mode from a Macbook Air with El Capitan ( and a firewire adapter)
Downloaded EL Capitan from App Store and directed it to the HDD of the MBP.
In fact I installed an OSX on a sleeping MBP. Wicked Appleness.
Close the bridge, reset NVRAM and SMC
Once El Capitan was installed on the HDD of the MBP 2011, I shut it down.
Ran the Adam EFI fix, rebooted in safe mode the new El Capitan and it worked !!
Opened the bridge.