.htaccess URL to lowercase - .htaccess

Question

How to alter following snippet of .htaccess file to achieve:
Now if it rewrites, it takes user from-to:
domain.com/TEST - domain.com/test
domain.com/subdir/TEST - domain.com/test
Needed behaeviour is:
domain.com/TEST - domain.com/test
domain.com/subdir/TEST - domain.com/subdir/test
Unwanted behaeviour occurs when webpage's index is at 'subdir' directory, instead directly under domain.com, as shown in first example above.
# URL to lowercase
# If there are caps, set HASCAPS to true and skip next rule
RewriteRule [A-Z] - [E=HASCAPS:TRUE,S=1]
# Skip this entire section if no uppercase letters in requested URL
RewriteRule ![A-Z] - [S=28]
# Replace single occurance of CAP with cap, then process next Rule.
RewriteRule ^([^A]*)A(.*)$ $1a$2
RewriteRule ^([^B]*)B(.*)$ $1b$2
RewriteRule ^([^C]*)C(.*)$ $1c$2
RewriteRule ^([^D]*)D(.*)$ $1d$2
RewriteRule ^([^E]*)E(.*)$ $1e$2
RewriteRule ^([^F]*)F(.*)$ $1f$2
RewriteRule ^([^G]*)G(.*)$ $1g$2
RewriteRule ^([^H]*)H(.*)$ $1h$2
RewriteRule ^([^I]*)I(.*)$ $1i$2
RewriteRule ^([^J]*)J(.*)$ $1j$2
RewriteRule ^([^K]*)K(.*)$ $1k$2
RewriteRule ^([^L]*)L(.*)$ $1l$2
RewriteRule ^([^M]*)M(.*)$ $1m$2
RewriteRule ^([^N]*)N(.*)$ $1n$2
RewriteRule ^([^O]*)O(.*)$ $1o$2
RewriteRule ^([^P]*)P(.*)$ $1p$2
RewriteRule ^([^Q]*)Q(.*)$ $1q$2
RewriteRule ^([^R]*)R(.*)$ $1r$2
RewriteRule ^([^S]*)S(.*)$ $1s$2
RewriteRule ^([^T]*)T(.*)$ $1t$2
RewriteRule ^([^U]*)U(.*)$ $1u$2
RewriteRule ^([^V]*)V(.*)$ $1v$2
RewriteRule ^([^W]*)W(.*)$ $1w$2
RewriteRule ^([^X]*)X(.*)$ $1x$2
RewriteRule ^([^Y]*)Y(.*)$ $1y$2
RewriteRule ^([^Z]*)Z(.*)$ $1z$2
# If there are any uppercase letters, restart at very first RewriteRule in file.
RewriteRule [A-Z] - [N]
RewriteCond %{ENV:HASCAPS} TRUE
RewriteRule ^(.*) /$1 [R=301,L]

Answer 1

Please, remove the .htaccess present inside /subdir because then your rule /$ would remove subdir from the input URL since that leading / makes it an absolute URL. From the root .htaccess, the rule would leave the URL unchanged (except changing the case).
Alternatively, if you have any sub-directory specific rules and want to keep your /subdir/.htaccess just change it's rule to RewriteRule ^(.*)$ $1 [R=301,L].