Joinder Agreement dated May 8, 2025 by and among YHN Acquisition I Limited, Mingde Technology Limited, YHNA MS I LIMITED and YHNA MS II LIMITED

Exhibit 10.1

JOINDER AGREEMENT

This JOINDER AGREEMENT, made and entered into as of May 8, 2025 (this “Joinder Agreement”), by and among YHN Acquisition I Limited, a British Virgin Islands business company (“Parent”), Mingde Technology Limited, a Cayman Islands exempted company (the “Company”), YHNA MS I LIMITED, a Cayman Islands exempted company and wholly owned subsidiary of the Parent (“Purchaser”) and YHNA MS II LIMITED, a Cayman Islands exempted company and wholly owned subsidiary of Purchaser (“Merger Sub”). Reference is made to that certain Business Combination Agreement (the “Business Combination Agreement”), dated as of April 3, 2025, entered into by and between Parent and the Company. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed to such terms in the Business Combination Agreement.

WHEREAS, Purchaser was formed on April 29, 2025 for the sole purpose of the merger of Parent with and into Purchaser, in which Purchaser will be the surviving entity;

WHEREAS, Merger Sub was formed on April 29, 2025 for the sole purpose of merging with and into the Company, with the Company being the surviving entity and becoming a wholly-owned subsidiary of Purchaser;

WHEREAS, pursuant to Section 7.10 of the Business Combination Agreement, Purchaser and Merger Sub are required to execute and deliver this Joinder Agreement;

WHEREAS, the parties hereto desire to execute this Joinder Agreement pursuant to which each of Purchaser and Merger Sub shall become party to the Business Combination Agreement; and

WHEREAS, the parties hereto desire to modify solely those provisions of the Business Combination Agreement as expressly set forth herein;

NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties to this Joinder Agreement hereby agree as follows:

1. Agreement to be Bound. Each of Purchaser and Merger Sub hereby agrees that upon execution of this Joinder Agreement, it shall become a party to the Business Combination Agreement and shall be fully bound by, and subject to, all of the covenants, terms, representations, warranties, rights, obligations and conditions of the Business Combination Agreement as though an original party thereto. Each of Parent and the Company consent to such joinder and the resulting amendment to the Business Combination Agreement.

2. Successors and Assigns. This Joinder Agreement shall be binding upon, enforceable by and inure to the benefit of the parties and their respective successors and assigns.

3. Entire Agreement. This Joinder Agreement represents the entire agreement between the parties hereto with respect to the subject matter hereof and, except as expressly provided in this Joinder Agreement or the Business Combination Agreement, supersedes all prior negotiations, representations or agreements, either oral or written, with respect to such subject matter.

4. Counterparts. This Joinder Agreement may be executed in separate counterparts each of which shall be an original and all of which taken together shall constitute one and the same agreement. This Joinder Agreement may be executed and delivered by facsimile or electronic transmission.

5. Governing Law. This Joinder Agreement and any claim, controversy or dispute arising under or related to this Joinder Agreement shall be governed by and construed in accordance with the laws (both substantive and procedural) of the State of Delaware, without giving effect to the conflict of laws principles thereof. Any dispute relating to this Agreement shall be resolved in accordance with the Dispute Resolution provisions set forth in Article XII of the Business Combination Agreement.

6. Headings. The headings contained in this Joinder Agreement are for convenience of reference only and shall not be deemed to alter or affect any provision hereof.

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IN WITNESS WHEREOF, the parties hereto have caused this Joinder Agreement to be effective as of the date first written above.