NUCLEO-F091RC: ST-LINK/V2-1 enumerates and drops in a ~0.3 s loop on macOS Tahoe (Apple silicon)

[LooselySubtle]

I have a NUCLEO-F091RC (on-board ST-LINK/V2-1, USB ID 0483:374b, latest firmware V2J33M25). When plugged directly into my Mac it enumerates and drops repeatedly. LD1 keeps blinking red.

I found the ST FAQ "Possible communication failure between STLINK-V3 and some recent computers" (eUSB2 repeater interoperability). My symptoms look very similar, but my probe is a V2-1 that enumerates at full speed (12 Mbps), not a V3, so I'd like to know if the V2-1 is affected too.

Setup

• MacBook Pro 14-inch (Nov 2023), Apple M3 Pro, macOS Tahoe 26.7.1
• USB-C to Mini-B cable, directly into the Mac

Symptom (from log stream, repeating about every 0.3 s):

 

enumerated 0x0483/374b/0100 (STM32 STLink / 1) at 12 Mbps
AppleUSBIORequest::complete: device 1 (STM32 STLink) endpoint 0x00: status 0xe00002ed (transaction error): 0 bytes transferred
AppleUSBHostPort::terminateDevice: destroying 0x0483/374b/0100 (STM32 STLink): hardware connection lost

ioreg -p IOUSB -w0 shows a new STM32 STLink entry with a different id every second or so. The full log is attached.

Ruled out

• Two USB-C ports on two different controllers behave the same.
• The same board and cable are stable on a Windows laptop.
• macOS accessory security is not blocking it: the log shows "Allow Automatically When Unlocked", authorization granted, 300 mA available.
• Nothing else is attached to the board.

Workaround found: a USB hub between the Mac and the board gives a stable connection. With it I can build, flash and debug from Keil in a Windows 11 ARM64 VM.

Questions

1. Is the ST-LINK/V2-1 on Nucleo boards affected by the same eUSB2 repeater issue as the V3?
2. Is there any fix other than a hub (firmware, hardware revision)? I need a reliable setup for an exam, so a hub is acceptable but not ideal.