digital mobile telephone service, including advanced calling features such as speakerphone, conference calling, voice-mail, call forwarding and additional line service

Exhibit 10.12

[FORM OF AMENDMENT NO. 004 TO iDEN INFRASTRUCTURE EQUIPMENT SUPPLY AGREEMENT]

AMENDMENT NO. 004

TO

iDEN INFRASTRUCTURE EQUIPMENT SUPPLY AGREEMENT

BETWEEN

COMMUNICACIONES NEXTEL DE MEXICO, S. A. DE C. V.,

NII HOLDING, INC. (f.k.a. NEXTEL INTERNATIONAL, INC.)

AND

MOTOROLA, INC.

This Amendment No. 004, dated as of the 30th day of December, 2003, is between on the one hand, Motorola, Inc., a Delaware corporation, by and through its Global Telecom Solutions Sector, with offices at 1421 West Shure Drive, Arlington Heights, Illinois, 60004 (“Motorola”), and, on the other, Communicaciones Nextel de Mexico, S. A. de C. V., a company with offices at Blvd. Manuel Avila Camacho No. 36, Piso 9, Colonia Lomas de Chapultepec, Mexico 11000, D.F., and NII Holdings, Inc. (formerly known as Nextel International, Inc.), a Delaware corporation, with offices located at 10700 Parkridge Boulevard, Suite 600, Reston, VA 20191 (collectively, “NII”; NII and Motorola to be collectively referred to as the “Parties”), and amends the iDEN Infrastructure Equipment Supply Agreement (“Agreement”) dated as of June 30, 2000, as heretofore amended, modified, supplemented, or otherwise revised. Capitalized terms used herein but not otherwise defined herein shall have the same meanings given to such terms in the Agreement.

WHEREAS, Motorola and NII entered into the iDEN Infrastructure Supply Agreement effective as of the 30th day of June, 2000 (hereinafter referred to as the “Existing Agreement”);

WHEREAS, the Existing Agreement is set to expire by its terms on December 31, 2003;

WHEREAS, Motorola and NII wish to extend the Existing Agreement to allow sufficient time to negotiate and execute a New Agreement, and it is their intention to execute the New Agreement as soon as practically possible, pending execution of a new equipment supply agreement between Motorola and Nextel Communications, Inc. (“NCI Contract”);

WHEREAS, substantially all of the terms and conditions of the Existing Agreement shall continue during the interim period prior to the Parties entering into the New Agreement, except for certain modifications that have been discussed between the Parties as more fully set forth below; and

WHEREAS, Section 34 of the Existing Agreement requires that all modifications thereto be in writing and executed by authorized representatives of both Parties.

NOW, THEREFORE, in consideration of the promises and mutual obligations contained herein and for other good and valuable consideration, the receipt and sufficiency of which are hereby mutually acknowledged, Motorola and NII agree as follows:

Motorola Confidential Proprietary