really thanks for your reply!
I think my problem here is related to the fact that high sierra tried to do something on the other disc (reading, trim, indexing, I don't know...).
The same operetion on a macbook pro 2019 doesn't cause this.
On this computer I initially created my hack directly for big sure and i was quitly proud of it
I'm really the only one that suffer this?
Ps. I never tried to boot big sur from high sierra, I used an usb open core 0.6.8 for it and for big sur I had a complete installation with OC 0.7.2 and port mapping.
This means that next time I want to use my hSierra I need to disconnect every BigSur drive from the system?
Anyway on a different bigsur installation I can read correctly and see the partitions in finder, but is a little messed in disk utility or in Open core menu