After deselescting los recoveri inside the rom I flashed twrp via pc with fastboot command, with no error .You need to flash TWRP via PC, LOS does not support recovery flash as far as I know. Then enter TWRP and flash via TWRP the TWRP recovery again, as described in the trail here before. Maybe you could tell us, if you were able to flash via PC successfully, again there should be a message after the fastboot command, otherwise your device is not correctly mounted
Here is the problem : I cannot enter this first twrp to reflash as you said because the system enter in LOS recovery again ! ( +/- button or launched with the rom menu ).
If my device isnt correctly mounted what can I do please ?
thanks a lot for your help