How to close the cpu0?

[Oceanisher]

We have a device with a multi-core CPU. And we run the linux OS on it. The CPU has eight cores in it and now we can close the other cores except the first core. Our requirement is that we want to open the other seven cores and close the first core. But it seems that the first core(cpu0) could not be closed.

Then how could we do to close it?

The command "echo 0 > /sys/devices/system/cpu/cpu0/online" can not work.

Thanks for your help!