R4930 G7 expansion NVMe drive not identified in BIOS

At a certain site, three R4930 G7 servers equipped with front 12FF (4 SAS/SATA + 8 UniBay, LSI Expander backplane) added NVMe drives. Among them, two encountered an issue where the drives were only detected in HDM but not in BIOS or OS.

The three servers differ only in the backplane model, all using PCA-BP-12LFF-EXP-2U-G6, but there are two codes

(1) Backplane model used in abnormal situations:

Spare part code: 0231AK79
Material code: 0302A6SL
Model: UN-PCA-BP-12LFF-EXP-2U-G6
Functional module-H3C UniServer R4900 G6 Ultra-RS3M8B12L-2U front 12LFF with Expander drive backplane module (CTO&BTO)-Domestic and overseas unified version

(2) Backplane model used in normal situations:

Spare part code: 0231AP96
Material code: 0302A8A9
Model: UN-PCA-BP-12LFF-EXP-A-2U-G6
Functional module-H3C UniServer R4950 G6-RS4M3B12L-2U front 12LFF with Expander drive backplane module (for AMD)(CTO&BTO)-Domestic and overseas unified version

Refer to the latest version (V1.39) specifications table. Only backplane 0302A8A9 is in use, which supports AMD and Hygon. Backplane 0302A6SL only supports AMD, not Hygon, and is no longer used in this model.

After replacing 0302A6SL with 0302A8A9, nvme was identified normally