How I replace the HDD of mycloud gen2

My Cloud OS 3 Personal & Network Attached Storage My Cloud
12

Hello,
I followed the instruction step by step
When I add the last 2 commands

cp uImage-wdrecovery /mnt/boot/boot/uImage
cp uRamdisk-wdrecovery /mnt/boot/boot/uRamdisk

I get an error no file or folder found.
Did I miss something?
Please advise.