Unsolved
1 Rookie
•
4 Posts
0
18
July 25th, 2025 13:04
PowerEdge R740xd BP1 A0/B0 not detected when using SFF-8654 cable
Hi all,
I'm working with a PowerEdge R740xd with a 24-bay NVMe backplane (BP1).
I installed one PCIe Extender Card in Slot 1 (controlled by CPU1), and connected it to the rightmost NVMe ports on the backplane, which are labeled A0 and B0 (corresponding to bays 21–24).
However, during POST I received the following error:
HWC2003: The storage BP1 PCIe A0 cable is not connected, or is improperly connected.
HWC2003: The storage BP1 PCIe B0 cable is not connected, or is improperly connected.
I'm using a third-party **SFF-8654 8i to 8i PCIe Gen4 cable** (no Dell branding), which may lack sideband or I2C channels.
As a test, I tried reconnecting the same cable to other ports (e.g. A2/B2), and the POST warning changed accordingly — indicating that the system *is* detecting which backplane ports are being used. This makes me wonder if the issue is specifically related to sideband detection or signaling.
So my questions are:
- Is the HWC2003 alert caused solely by the lack of sideband signaling in non-Dell cables?
- If so, will the NVMe lanes still function for actual data transfer despite the warning?
- Can this alert be suppressed in BIOS, or is it necessary to use Dell-specific cables with full signaling?
Thank you very much for any advice!
DELL-Charles R
Moderator
•
4.4K Posts
0
July 25th, 2025 17:24
Hello,
The error is likely because it is not using the Dell cable.
I don't know of any way to suppress the errors and I don't know if the cable would work but you can try it.
Was this sold originally with the 24x2.5 inch NVMe drive backplane?
I ask that because field change of backplane configuration is not typically supported because we don't have kits for that.
Do you confirm this is the configuration you have:
Page 155 -
Figure 153. Cable routing – 24 x 2.5 inch NVMe drive backplane
cable 10 and 9
https://dl.dell.com/content/manual43110904-dell-emc-poweredge-r740xd-installation-and-service-manual.pdf?language=en-us
This looks to be the cable you need:
Part Number
Part Description
Functional Description
X7MYJ
ASSY,CBL,PCIE3,X24,RSR1,R740XD
X24 Expander to Riser 1 bridge
DELL-Charles R
Moderator
•
4.4K Posts
0
July 25th, 2025 19:47
Hello,
I searched some and I believe this should be the cable:
Part #:W6N4M
Part Desc.:ASSY,CBL,ADPT,2.5X24,RSR1,R740
ASSY 24X2.5 Backplane to Bridge Card Riser 1 PCIE Cable
RickyChen
1 Rookie
•
4 Posts
0
July 26th, 2025 11:07
Hi,
Thank you for the information.
Just to clarify — currently I have the enclosure mode set to "Unified Mode", and I'm connecting to ports A0 and B0 only (the rightmost NVMe ports on BP1, corresponding to bays 21–24).
My questions:
Do I need to change the enclosure mode to something like
"Split Mode - 20:4"for the A0/B0 ports to work correctly?Or is "Unified Mode" sufficient if I only use the A0/B0 ports with the PCIe extender connected to Riser 1?
Appreciate your clarification.
Best regards,
DELL-Young E
Moderator
•
5.1K Posts
0
July 28th, 2025 01:10
Hello,
All the cabling options in the user guide
Dell EMC PowerEdge R740xd Installation and Service Manual | Dell US
Dell EMC PowerEdge R740xd Installation and Service Manual | Dell 日本
poweredge-r740xd | Dell EMC PowerEdge R740xd Installation and Service Manual | cable-routing
I'm not sure how you modified the system, but you need to use one of the supporting cabling options, and definitely not to use 3rd party cables, might I add.
Respectfully,