By changing the RewriteRule (and eliminating the RewriteBase). The regex should be .? and the redirection is, obviously, http://m.mysite.com%{REQUEST_URI}. Go figure.
A refinement, if I may: Be sure to use that code in the .htaccess of the domain’s DocumentRoot, NOT in the DocumentRoot of the subdomain (the subdirectory of the domain). Otherwise, the code would be loopy. I’m sure that’s the case you have setup (m being a subdomain of mysite.com and physically located in the m subdirectory of mysite.com, i.e., mysite.com/m) so this refinement is for others who may encounter the same type of problem.
If you’re baffled by regex, please read the Regex section of the tutorial article linked in my signature.
As it stands, your code appears fine for the normally configured server, i.e., m is a subdomain physically located in the domain’s m subdirectory. If it’s not, please identify how your server is setup.
RewriteEngine On
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} android.+mobile|avantgo|bada\\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge\\ |maemo|midp|mmp|netfront|opera\\ m(ob|in)i|palm(\\ os)?|phone|p(ixi|re)\\/|plucker|pocket|psp|symbian|treo|up\\.(browser|link)|vodafone|wap|windows\\ (ce|phone)|xda|xiino [NC,OR]
RewriteCond %{HTTP_USER_AGENT} ^(1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a\\ wa|abac|ac(er|oo|s\\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\\-m|r\\ |s\\ )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\\-(n|u)|c55\\/|capi|ccwa|cdm\\-|cell|chtm|cldc|cmd\\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\\-s|devi|dica|dmob|do(c|p)o|ds(12|\\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\\-|_)|g1\\ u|g560|gene|gf\\-5|g\\-mo|go(\\.w|od)|gr(ad|un)|haie|hcit|hd\\-(m|p|t)|hei\\-|hi(pt|ta)|hp(\\ i|ip)|hs\\-c|ht(c(\\-|\\ |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\\-(20|go|ma)|i230|iac(\\ |\\-|\\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt(\\ |\\/)|klon|kpt\\ |kwc\\-|kyo(c|k)|le(no|xi)|lg(\\ g|\\/(k|l|u)|50|54|\\-[a-w])|libw|lynx|m1\\-w|m3ga|m50\\/|ma(te|ui|xo)|mc(01|21|ca)|m\\-cr|me(di|rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\\-|\\ |o|v)|zz)|mt(50|p1|v\\ )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\\-2|po(ck|rt|se)|prox|psio|pt\\-g|qa\\-a|qc(07|12|21|32|60|\\-[2-7]|i\\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\\-|oo|p\\-)|sdk\\/|se(c(\\-|0|1)|47|mc|nd|ri)|sgh\\-|shar|sie(\\-|m)|sk\\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\\-|v\\-|v\\ )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\\-|tdg\\-|tel(i|m)|tim\\-|t\\-mo|to(pl|sh)|ts(70|m\\-|m3|m5)|tx\\-9|up(\\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\\-|\\ )|webc|whit|wi(g\\ |nc|nw)|wmlb|wonu|x700|yas\\-|your|zeto|zte\\-) [NC]
[COLOR="#A9A9A9"]# ONLY if necessary, i.e., co-located mobile subdirectory
RewriteCond %{HTTP_HOST} !^w\\.mysite\\.com [NC][/COLOR]
RewriteRule .? http://mysite.com/mobile%{REQUEST_URI} [R,L]