Hi
If you already have a uTasker commercial full license you can use it for any Kinetis part and any number of products. The uTasker project includes KBOOT UART loader for KL02 (http://www.utasker.com/kinetis/FRDM-KL02Z.html about 6k in size) as well as UART SREC/iHEX loaders or I2C slave (see this video https://www.youtube.com/watch?v=awREsqeCEzQ&list=PLWKlVb_MqDQFZAulrUywU30v869JBYi9Q&index=22).
If you have been using the open source version in the past it also contains the KBOOT UART method.
Should you need support but can't afford commercial licensing or you are not allowed to invest in software and services you can also request a free commercial license which is supported free at this forum and is designed to help start-ups that are not yet profitable to quickly get their first product into production.
You could also take a look at the KL03 rather than the KL02 since it has the KBOOT UART method in its internal ROM LOADER that will not requre the serial loader to take up any Flash space of these smaller Flash devices.
Regards
Mark
Complete Kinetis solutions for professional needs, training and support: http://www.utasker.com/kinetis.html