I wanted to compile my kernel from sources. I needed to add one line in .config file, because that option is not possible to change by 'make menuconfig' (it is there when I search with '/' but there is no access to change it in menu).

But then when I start compilation, these lines are shown at startup:

scripts/kconfig/conf --silentoldconfig Kconfig
# configuration written to .config
and my .config is saved as .config.old file and new .config is created.

How can I use my manually modified .config file?