Off-Topic, but perhaps the expertise is here?

We are trying to package a custom kernel for the Raspberry Pi. (preempt-rt as a deb package)

It's here, if you want to play with it.

http://www.linuxcnc.org/dists/buster/base/binary-armhf/linux-image-4.19.71-rt24-v7l+_4.19.71-rt24-v7l+-4_armhf.deb

If one tries to install it one gets the following error messages:

dpkg: error processing archive ../linux-image-4.19.71-rt24-v7l+_4.19.71-rt24-v7l+-8_armhf.deb (--install)

[5:41pm] unable to make backup link of './boot/System.map-4.19.71-rt24-v7l+' before installing new version: Operation not permitted

dpkg-deb: error: paste subprocess was killed by signal (Broken pipe)

Is there anything that we can do inside the package to circumvent this?

atp
"A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912