I don't REALLY know the size but judging by the update notes..
The only things that changed are stability and that the Nintendo TVii icon is gone because it was shut down
See by yourself, I don't really see how tf does it take more than 100mb even, but DON'T RELY on my answer, you should make sure with other ppl:
Version 5.5.2 U:
Released July 17th, 2017
Improvements to system stability and usability:
- Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience
Version 5.5.1 U:
Released January 11th, 2016
Improvements to system stability and usability:
- Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience
Version 5.5.0 U
Released August 17th, 2015
Changes to the Wii U Menu and HOME Menu:
- The Nintendo TVii icon has been removed from the Wii U Menu and HOME Menu. For more information regarding the end of this service, click here.
Improvements to system stability and usability:
- Further improvements to overall system stability and other minor adjustments have been made to enhance the user experience