Mcp2517fd works, but mcp2518fd doesn't?!

What works:

  • Raspberry Pi 4B 4GB with Seeed Studio CAN-HAT (the old version without an RTC)
  • Raspberry Pi OS (Raspbian GNU/Linux 10 with kernel 5.10.103-v71+)
  • compiled driver from Seeed’s git, included using /boot/config.txt: dtoverlay=2xMCP2571FD.dtbo
  • using two udev rules as sometimes, the OS switched can0 and can1 (I need both!)
  • acoording to dmesg, mcp251xfd gets loaded and finds two mcp2518fd rev0.0 connected to spi0.1 and spi1.0
    → interfaces can0 and can1 are being created, I can RX and TX stuff from a device connected to one of the CAN buses

What works partially:

  • Raspberry Pi 4B 4GB with Seeed Studio CAN-HAT (the new version with an RTC)
  • Raspberry Pi OS (Raspbian GNU/Linux 10 with kernel 5.10.103-v71+)
  • /boot/config.txt: dtoverlay=seed-can-fd-hat-v2
  • no udev rules
  • acoording to dmesg, mcp251xfd gets loaded and finds two mcp2518fd rev0.0 connected to spi0.1 and spi0.0 (that’s different compared to what I wrote above!)
    → interfaces can0 and can1 are being created, but I cannot RX any packets using candump ALTHOUGH ifconfig -a is showing 261589 sent and 718030 received packets and dmesg shows some CRC read errors on can0

What am I getting wrong here?