Allwinner H618 custom board

(BA882_141_V1.0) flashing fails at 44% with error 0x161

Body: I am trying to flash a custom Allwinner H618 Android TV box / embedded board (Model: BA882_141_V1.0 22244) from a defunct manufacturer, and I don't have the original backup firmware.

Details:

• SoC: Allwinner H618
• RAM Chips: 4x 4EE77 D9QBQ (batch codes vary slightly: HFB7, H8JP, HHTC)
• Symptom: Every compatible firmware I've tried stops flashing at around 44%–45% and throws error 0x161 (Download Boot Failed). The front display doesn't light up, and only the optical port LED stays on.
• What I've tried: Tested multiple generic firmwares matching the hardware, but they all fail at the bootloader/DRAM initialization stage due to missing custom boot parameters.

Is there a known workaround, or a way to build/modify a compatible bootloader or DRAM configuration to bypass this error without the original factory firmware?