Porting B2G build on nexus 5 on OSX

I am facing issues when building .

i have a OSX which is macOS Sierra. i ran all the build steps i have an xcode 5.1 too and xcode latest . i downloaded all the tools through the lastest xcode and switched back to 5.1 for building . The build comes till the below point and stops with out any error , how do i get my system image .

WARNING: Found 35 duplicated files taking 84939 bytes (33952 compressed)

Package mozharness

/Volumes/firefoxos/B2G/objdir-gecko/_virtualenv/bin/python -m mozbuild.action.test_archive mozharness /Volumes/firefoxos/B2G/objdir-gecko/dist/mozharness.zip
Wrote 460 files in 659246 bytes to mozharness.zip in 0.39s
cd …/…/dist && (cd b2g && /Volumes/firefoxos/B2G/objdir-gecko/_virtualenv/bin/python /Volumes/firefoxos/B2G/gecko/config/createprecomplete.py) && /usr/local/bin/gtar -c --owner=0 --group=0 --numeric-owner --mode=go-w --exclude=.mkdir.done -f - b2g | gzip -vf9 > b2g-52.0a1.en-US.linux-androideabi-arm.tar.gz
touch make-package
make[3]: Nothing to be done for `tools’.

Steps which i have followed to start the build:-

curl -fsSL https://raw.github.com/mozilla-b2g/B2G/master/scripts/bootstrap-mac.sh | bash

the above command gave me that i could start build now .

Download the code and started the build on a nonsensitive drive created on OSX

./config nexus-5

Any suggestion on what i need to do ?