The MRD-LX1 uses a 5000mAh battery. If the battery drops below 2.5V, the charging IC enters a trickle-charge mode. The phone appears dead, but the boot is intact. This is a pseudo-dead boot, but many mistake it for a real firmware brick.
This method works if the phone can enter (Basic ROM mode). BROM is a read-only memory inside the MediaTek CPU that cannot be corrupted. If your PC reacts when you connect the phone, you can save it. mrd-lx1 dead boot repair
If the phone does not enter BROM via buttons, you need to short the test points on the motherboard: The MRD-LX1 uses a 5000mAh battery