Model/board: SER5 Plus 5800H, silkscreen AZW_Ser4 V1.3. Ports: 2×HDMI (no DP). Unit is 0+0g (no RAM/SSD). RAM used for testing: Crucial DDR4-3200 SODIMM CL22 1.2V (non-ECC). PSU is the Beelink 19V brick.
Symptoms: powers on (white LED), USB devices get power, long-press powers off. No splash or BIOS on either HDMI with multiple cables/1080p screens. I know an M.2 isn’t required to get video.
Tried:
RAM isolation: each Crucial stick tested alone in each slot, firmly seated (latches clicked). Same result: no video.
Display sanity: both HDMI ports, different cables and 1080p monitor/TV.
CMOS resets:
Front CLR-CMOS pinhole held 10–15 s with power removed, waited 10 min → no change.
Deep CMOS: unplugged J_BAT (CMOS battery) 10–15 min, held power 20–30 s, reconnected → no change.
USB/UEFI blind BIOS recovery:
USB prepared on macOS as FAT32/MBR.
Files on USB root: EFI/BOOT/BOOTX64.EFI (UEFI shell), AfuEfix64.efi, 5800HBSER1.506, flash.nsh, startup.nsh (wrapper writes start.flag, calls flash.nsh, writes done.flag, reset).
Procedure: deep CMOS → install one SODIMM → USB in rear port → power on, wait >10 min.
Result: after power-off, no start.flag on the USB (tried both rear USB ports). So it never reached the UEFI shell/startup.nsh.
Current state: still no HDMI output at all; appears not to reach EFI from USB after proper CMOS clears and minimal config.
Requests:
Please confirm the correct BIOS package for SER5 Plus 5800H dual-HDMI on AZW_Ser4 V1.3 (I can provide SN photo).
Is there a boot-block/force-recovery method or key combo to guarantee EFI-shell/USB start on this board?
Given the above, does this indicate a mainboard/video subsystem failure that warrants RMA?
I can provide SN, PSU label, and exact Crucial part numbers. I’m willing to try the older v502 dual-HDMI package if recommended.
