I have run into the same problem (as i have a optimus laptop too by looking at your spec).

Basically, some dgpu in optimus laptop don't have the rom loaded from the gpu directly (afaik most desktop gpu do the reverse here) or just don't have enough permissions to do it, or even because the gpu is still in use (aka most optimus gpu don't support hotswapping); afaik that's all the reason i can think of but i could be wrong.
But fortunately, there is still ways to get the rom of the gpu:

• On windows, the rom is loaded as a .reg file in the registry, so you can get it there (more info here)
• You can use either vbiosfinder or romparser on the update/dump of your bios (romparser is already included in vbiosfinder btw).which you can usually find on the manufacturer site or if normal dumping tools support your bios already...
• If the above doesn't work (which would surprise me, but just in case), you can use binwalk on each file from the bios dump until you see something akin to "manufacturer's name" or "gpu vendor" or anything similar.

I have some problem with some older cards, especially ATI ones.. On normal desktop PC.

you can only get the rom file in BIOS boot mode it seems, try boot your system in legacy mode with a linux distro and do that again.

root@pve:/# cd /sys/bus/pci/devices/0000:02:00.0/
root@pve:/sys/bus/pci/devices/0000:02:00.0# echo 1 > rom
root@pve:/sys/bus/pci/devices/0000:02:00.0# cat rom > /tmp/image.rom
cat: rom: Input/output error
root@pve:/sys/bus/pci/devices/0000:02:00.0# echo 0 > rom

My PVE system shows this. What should I do?

@sjkhsl,
As abigchopstick said, try booting in Legacy mode from USB using another distro.
I used Ubuntu Server and successfully dumped my ROM the usual way.

I want to dump the rocketlake rom, is it possible?