# Collection thread：U1 Top-Cover Mod

**URL:** https://forum.snapmaker.com/t/collection-thread-u1-top-cover-mod/40429
**Category:** U1 Featured Showcase Collection
**Tags:** Modification, hardware, U1
**Created:** [November 22, 2025, 6:55am UTC](https://forum.snapmaker.com/t/collection-thread-u1-top-cover-mod/40429 "2025-11-22T06:55:38Z")
**Posts on this page:** 1
**Showing post:** 31

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### Author: ![Printoid](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/printoid/32/33529_2.png) [@Printoid](https://forum.snapmaker.com/u/Printoid)
#### Post date: [March 25, 2026, 9:33am UTC](https://forum.snapmaker.com/t/collection-thread-u1-top-cover-mod/40429/31 "2026-03-25T09:33:34Z")

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@Simon_Zhi

Thank you for this information!  
This is very helpful.

Is it possible to tell us the purpose and use of the FLAG and FLAG2 pins in the top cover connector?

How does the printer firmware use or interpret these pins?

Thank you for supporting us with technical details and encouraging community improvements and designs!

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