@ixtab, thanks.
localedef --add-to-archive changes Amazon-provided file. This is not so good. It could prevents future updating to new original firmware. Instead, directory with locale definition could just be copied to 
/usr/lib/locale. It works.
It will be also good to add appropriate locale definitions, not the copy of 
en_US.utf8. I've tried to copy 
ru_RU locale definition file and 
UTF-8 character map (both from glibc Git repo: see 
locales and 
charmaps) to KT and compile them there with 
	Code:
	localedef -f charmap_file -i locale_file --no-archive /tmp/ru_RU.utf8
 It required also to download a lot of additional locale definitions, which 
ru_RU inherites from, but in the end  successfully produced directory 
/tmp/ru_RU.utf8 with compiled locale definition.