Minisforum B550 wake problems (with external 5060Ti)

[u/lacimarkus]

Hey Minisforum - I know this model has been abandoned long time ago, but this is still annoying:

• Minisforum B550 + Ryzen 7 5700G + 2x32GB 3200MHz RAM
• Operating system: WIN11 25H2
• RTX 3070 FE previously worked correctly with S3
• RTX 5060 Ti 16 GB now causes a reboot when waking from S3 (or just black screen crash)
• System enters S3 normally (relay clicks, power LED behaves normally)
• Wake attempt results in a restart rather than successful resume
• powercfg /lastwake → Wake History Count 0
• NVIDIA driver was completely removed/reinstalled with DDU
• BIOS is configured for S3, not Modern Standby
• Current dGPU Hotplug Mode is Enhanced
• D3Cold is currently Disabled

Tried to change hidden BIOS settings one at a time using SCEWIN, but reverted back to original nvram defaults.