Clone one partition and boot from USB

Linux and Unix-Like Ubuntu
1

I have small problem: my hard drive has 500GB storage and it is divided into partitions

/dev/sda1 - 20 GB (boot)
/dev/sda2 - rest

I want to clone only one partition

/dev/sda1

and write all data on my USB stick

/dev/sdb

What's more I want to make my USB bootable and I don't know at all how can I do that (if it is possible to clone only one partition and properly modify MBR in order to boot from USB).

2

First, does your PC support USB boot?

3

Yes, without any problems.

4

Maybe see if you can get a bootable Ubuntu image for USB and install that, then put your Ubuntu over it, or in a subdirectory where you can cross-mount it. I am not a usb linux boot guru, but maybe there is one around. ubuntu\ usb\ image - Google Search