I have a validated Duo acting as my rpi5 boot device. I need to add another pcie modem, so put in a waveshare 1 to 4 pcie splitter.
The duo no longer boots. All cables carefully checked.
Any known issues or suggestions?
best
My suggestion: boot from a SD-card (or USB-stick) and then analyze the system log. Also, you have commands like lspci -t -v that can give you insights into your PCIe infrastructure. Once up and running, check if you can mount your SSD. If so, this might be a workaround: boot from SD and run the system from SSD. I have some SSD that don’t boot but are perfect as a root-device, and this strategy has always been a safe fallback.
You might just have a latency problem which prevents booting, but this is just a quick guess.