It overwrite a custom files.

This "hardcoded" file is sync in "copycommon" function, called after "preparechroot" function where the lines :
    info "making /etc/hostname"
    echo "${HOSTNAME}" > "${BUILD_PATH}/etc/hostname"
create that file.
Independent of the platform, we find always the same hostname from that file.
Resolution : deleting the file.

common/etc/hostname

@@ -1 +0,0 @@
-pi.raspberry