Depending where you need an alternate layout.
In the emulationstation, the keyboard definition stands in recalbox.conf
------------ F - Language and keyboard ------------
Set the language of the system (fr_FR,en_US,en_GB,de_DE,pt_BR,es_ES,it_IT,eu_ES,tr_TR,zh_CN)
system.language=en_US
set the keyboard layout (fr,en,de,us,es)
;system.kblayout=us
Set you local time
Select your timezone from : ls /usr/share/zoneinfo/ (string)
;system.timezone=Europe/Paris
Now, if you want to use the keyboard for dosbox, you have a line in every dosbox.cfg
individual in the corresponding xxxxx.pc directory, or if you use the global dosbox.conf
inside this :
keyboardlayout=de129 means german keyboard.
Now the description in Dosbox is not very correct.
Better to follow this page for codes :
https://superuser.com/questions/1080381/keyboard-layout-setting-in-dosbox-has-no-effect