LG G4 (H815) - DualRecovery (Locked Bootloader) - Fastboot/ADB

I found out my phone's (H815L) bootloader can not be unlocked through LG :(
The phone is rooted ('system-update' + root) and I can use Fastboot/ADB to get into recovery, but it errors and won't recognize the custom recovery. Ok.
I am wondering if there is a DualRecovery for the LG G4 for 'Locked Bootloader' to flash/push through Fastboot/ADB?