ESP8266 webserver http header trouble with Content-Encoding

[avc]

I am stuck with a gzip header issue. I have ARduino Due + ESP8266 + SD card shield. I am also using https://github.com/itead/ITEADLIB_Ardui ... ee/develop There is an html file that is gzipped and saved on an SD card. Basic webserver operations are working. My issue is with http headers.

ESP8266:

AT Version: 0.60.0.0(Jan 29 2016 15:10:17)
SDK version:1.5.2(7eee54f4)
Ai-Thinker Technology Co. Ltd

If I do not send "Content-Encoding: gzip", then the gzipped content is served, but shown as garbled text offcourse. If I do send the gzip header, then after the headers, the ESP returns an error "link is not valid". And it is not able to send the contents.

Anyone knows what is the issue here?