HP T750 G2 UPS connected over USB to HP Z600: very slow BIOS, normal speed after boot.

[Pierre_Henri]

Hi helpers,

I bought a refurbished HP Z600 workstation, and a refurbished HP T750 G2 UPS. The Z600 has both sockets populated with Xeon X5670 processors, and with 96GB ECC RAM. The O/S is Kubuntu Linux version 18.04 LTS.

Both the Z600 and T750 appear to work perfectly well, except for one thing: When the Z600 restarts with the T750 connected over USB, the BIOS response speed drops dramatically, and so does the GRUB bootloader, but only until the O/S begins to take over. Once in the O/S, everything runs as fast as usual.

I am considering a BIOS upgrade to see if that will solve or improve the BIOS boot speed problem. Has anyone else observed similar, where a USB device causes BIOS to boot very slowly? Will a BIOS upgrade provide a solution, from your experience?

Pete.

[Pierre_Henri]

Minor update: The slow BIOS is avoided if a USB hub is inserted between the T750 and the Z600. Not yet sure if the hub will interfere when the Z600 is in suspend, and the T750 attempts to alert the Z600 for it to wake from suspend and perform an orderly shutdown and power-off.

[Pierre_Henri · Accepted solution]

Final solution: With a generic USB to RS232 cable, I am able to avoid the slow BIOS at boot time, and benefit from comms with the T750.