 		relPath = path.relative(path.resolve(dir), file)
 		Promise.join relPath, fs.stat(file), fs.readFile(file),
 			(filename, stats, data) ->
-				pack.entryAsync({ name: filename, size: stats.size, mode: stats.mode }, data)
+				pack.entryAsync({ name: toPosixPath(filename), size: stats.size, mode: stats.mode }, data)
 	.then ->
 		pack.finalize()
 		return pack


					if options.emulated and platformNeedsQemu()
						buildThroughStream = transpose.getBuildThroughStream
							hostQemuPath: qemuPath
							containerQemuPath: "/tmp/#{QEMU_BIN_NAME}"

						newStream = stream.pipe(buildThroughStream)

						# if we need emulation
						if options.emulated and platformNeedsQemu()
							return transpose.transposeTarStream buildStream,
								hostQemuPath: toPosixPath(qemuPath)
								containerQemuPath: "/tmp/#{QEMU_BIN_NAME}"
						else
							return buildStream
