fix: syslinux install but not bootable

1. set syslinux install with -i
2. active partition with sfdisk
3. fix some log issue

tower: https://tower.im/projects/5561a1eca9d14ee2811802983b1b1622/todos/3db8aea1c4214b2eb4399f60af5d1cd7/

Change-Id: Ib1c90473f1c57fb2ba748ec463b045a6f387d6a4