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                                                                     EXHIBIT 2.5

                          FIRST SUPPLEMENTAL INDENTURE



          FIRST  SUPPLEMENTAL  INDENTURE,   dated  as  of  May  12,  2003  (this
"Supplemental Indenture"),  between AZTECA HOLDINGS, S.A. DE C.V., a corporation
(sociedad anonima de capital variable)  established under the laws of the United
Mexican States (the  "Company"),  having its principal  office at Periferico Sur
No. 4121, Colonia Fuentes del Pedregal,  14141, Mexico, D.F. and THE BANK OF NEW
YORK, a New York banking corporation, as trustee (the "Trustee").

          WHEREAS,  the Company  and the  Trustee  are  parties to that  certain
Indenture, dated as of January 31, 2002 (the "Indenture"), pursuant to which the
Company  issued  US$150,000,000  in  aggregate  principal  amount of its 10 1/2%
Senior Secured Notes due 2003 (the "Notes");

          WHEREAS, Section 9.02 of the Indenture provides that modifications and
amendments to the Indenture may be made and one or more indentures supplement to
the  Indenture  may be entered  into by the  Company  and the  Trustee  with the
written  consent of the  holders  (the  "Holders")  of a majority  in  aggregate
principal  amount  of  the  Notes  outstanding,   except  for  certain  specific
modifications  or  supplements  which require the unanimous  written  consent or
unanimous affirmative vote of the Holders of the Notes;

          WHEREAS,   the  Company   undertook  an  exchange  offer  and  consent
solicitation  pursuant  to  an  Offering  Memorandum  and  Consent  Solicitation
Statement,  dated March 3, 2003, as supplemented by a Supplement to the Offering
Memorandum  and  Consent  Solicitation  Statement,  dated  April  25,  2003 (the
"Offering  Memorandum"),  offering to exchange the Holders' Notes for its new 10
3/4% Senior Secured  Amortizing  Notes due 2008 (the "New Notes") and requesting
that the Holders give their written  consent to implement the  amendments to the
Indenture set forth in this Supplemental Indenture;

          WHEREAS,  the Company has received the valid  written  consents of the
Holders of at least a majority in aggregate  principal amount outstanding of the
Notes consenting to so amend the Indenture;

          WHEREAS,  all  conditions  and  requirements  necessary  to make  this
Supplemental Indenture a valid, binding, and legal instrument in accordance with
the terms of the Indenture  have been  performed and fulfilled and the execution
and delivery hereof have been in all respects duly authorized; and

          WHEREAS,  in accordance  with the terms of the Indenture,  the Company
has requested that the Trustee execute and deliver this Supplemental Indenture.

          NOW,  THEREFORE,  in consideration of the foregoing and for other good
and valuable  consideration,  the receipt of which is hereby  acknowledged,  the
Company and the


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Trustee  hereby  agree for the  benefit of each other and the equal and  ratable
benefit of the Holders of the Notes as follows:

                                   Article I

                              INDENTURE AMENDMENTS

          Section 1.01 Amendments to Indenture.  The Indenture is hereby amended
                       -----------------------
as follows:

          (a)  The table of contents of the  Indenture is hereby  amended by (i)
               replacing the heading  "Limitation on Other Business  Activities"
               in Section 4.06 with the heading "[intentionally  omitted];" (ii)
               replacing the heading  "Limitation on Indebtedness of the Company
               and  Limitation on Preferred  Stock of TV Azteca" in Section 4.07
               with the heading  "[intentionally  omitted];" (iii) replacing the
               heading   "Limitation  on  Indebtedness  of  TV  Azteca  and  its
               Restricted   Subsidiaries"  in  Section  4.08  with  the  heading
               "[intentionally omitted];" (iv) replacing the heading "Limitation
               on Restricted  Payments" in Section 4.09 with the heading  "Asset
               Disposition  Proceeds  Offer  to  Purchase;"  (v)  replacing  the
               heading  "Limitation  on Dividend and Other Payment  Restrictions
               Affecting Certain  Subsidiaries" in Section 4.10 with the heading
               "[intentionally  omitted];" (vi) replacing the heading  "Required
               Stock  Ownership;  Limitation  on Liens" in Section 4.11 with the
               heading  "[intentionally  omitted];"  (vii) replacing the heading
               "Limitation on Sale and Leaseback  Transactions  by TV Azteca and
               its  Restricted  Subsidiaries"  in Section  4.12 with the heading
               "[intentionally   omitted];"   (viii)   replacing   the   heading
               "Limitation on Asset Dispositions by TV Azteca and its Restricted
               Subsidiaries"  in Section  4.14 with the heading  "[intentionally
               omitted];" (ix) replacing the heading "Limitation on Transactions
               with Affiliates" in Section 4.15 with the heading "[intentionally
               omitted];"  (x)  replacing  the heading  "Limitation  on Interest
               Rate,  Currency or Commodity  Price  Agreements"  in Section 4.16
               with the heading  "[intentionally  omitted];"  (xi) replacing the
               heading "Provision of Financial Information" in Section 4.17 with
               the  heading  "[intentionally   omitted];"  (xii)  replacing  the
               heading "Limitation on Designation of Unrestricted  Subsidiaries"
               in  Section  4.18  with the  heading  "[intentionally  omitted];"
               (xiii) replacing the heading "Merger,  Consolidation  and Certain
               Sales of Assets" of  Article V with the  heading  "[intentionally
               omitted];"  and (xiv)  replacing  the  heading  "Cure,  Waiver or
               Rescission of  Cross-Acceleration  or Payment Default" of Section
               6.04 with the heading "[intentionally omitted]."

          (b)  Section 1.01 of the  Indenture  is hereby  amended to include the
               following definitions:


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               "Exchange  Offer"  means  the  Company's  offer to  exchange  the
               Holders'  Notes  for  New  Notes  made  pursuant  to an  Offering
               Memorandum  and Consent  Solicitation  Statement,  dated March 3,
               2003, as supplemented by a Supplement to the Offering  Memorandum
               and Consent Solicitation Statement, dated April 25, 2003.

               "New Notes" means the US$80,082,000 in aggregate principal amount
               of the  Company's  10 3/4% Senior  Secured  Amortizing  Notes due
               2008.

               "Release  Percentage" means 76.694% of the 2003 TV Azteca Pledged
               Shares held  pursuant to the CPO Pledge  Agreement on the date of
               the consummation of the Exchange Offer.

          (c)  The  definition of "2003 Unefon Rights" set forth in Section 1.01
               of the Indenture is deleted in its entirety and replaced with the
               following:

               "2003  Unefon  Rights"  means the Unefon  Rights with  respect to
               34,310,092  ordinary,  no par value, Series "A" shares of Unefon,
               consisting  of (i)  4,837,106  shares of Capital  Stock of Unefon
               that may be  acquired  pursuant  to the  exercise  of the  Unefon
               Rights associated with the 2003 TV Azteca Pledged Shares and (ii)
               29,472,986 shares of Capital Stock of Unefon that may be acquired
               pursuant to the  exercise of the Unefon  Rights  associated  with
               235,358,095 Azteca Holdings Series A Shares.

          (d)  Article IV is  amended by  deleting  the text of  Sections  4.06,
               4.07,  4.08, 4.10, 4.11, 4.12, 4.14, 4.15, 4.16, 4.17 and 4.18 in
               their   entirety   and   inserting   in  lieu  thereof  the  text
               "[intentionally omitted]."

          (e)  The words  "Limitation on Restricted  Payments" in the heading to
               Section  4.09 are  deleted  and  replaced  with the words  "Asset
               Disposition Proceeds Offer to Purchase."

          (f)  Section  4.09 is amended  by  deleting  all of the text  thereof,
               except for the text contained in subparagraph (d)(i). The text of
               such  subparagraph  is amended by deleting the words "60 days" in
               the first line and  replacing  them with the words "6 months" and
               by deleting the words  "pursuant  to Section  4.14" in the second
               line and  replacing  them with the words "with the proceeds of an
               Asset Disposition."

          (g)  Section  4.13 is amended by  deleting  the words "30 days" in the
               first line and replacing them with the words "6 months."

          (h)  The text of  Article  V is hereby  deleted  in its  entirety  and
               replaced with the text "[intentionally omitted]."

          (i)  Sections  6.01(e),  (f),  (g), (h) and (i) are hereby  deleted in
               their entirety.


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          (j)  Section  6.02 is  amended by  deleting  the first  sentence.  The
               second  sentence of Section 6.02 is amended by deleting the words
               "any other" and replacing them with the word "an."

          (k)  Section  6.04 is amended by deleting the text in its entirety and
               inserting in lieu thereof "[intentionally omitted]."

          (l)  A new Section 11.04(j) is included in the Indenture
                           to read as follows:

               Notwithstanding  anything to the contrary  contained herein,  the
               Trustee shall instruct the 2003 Collateral  Agent to release from
               the CPO Pledge  Agreement on May 12, 2003 in connection  with the
               consummation of the Exchange  Offer,  that portion of the 2003 TV
               Azteca Pledged Shares equal to the Release Percentage.

          Section 1.02 Mutatis Mutandi Effect.  The Indenture,  as supplemented,
                       ----------------------
is hereby amended  mutatis  mutandi to reflect  amendments  described in Section
1.01 hereof.

                                   Article II

                                  MISCELLANEOUS

          Section  2.01 Terms  Defined.  For all  purposes of this  Supplemental
                        --------------
Indenture,  except as otherwise  defined herein,  capitalized terms used in this
Supplemental  Indenture  shall have the  meanings  ascribed to such terms in the
Indenture.

          Section 2.02 Indenture  Ratified.  Except as expressly amended hereby,
                       -------------------
the Indenture  and the Notes are in all respects  ratified and confirmed and all
the terms,  conditions  and  provisions  thereof  shall remain in full force and
effect.  From and after the  effectiveness of this Supplemental  Indenture,  any
reference  to the  Indenture  shall  mean the  Indenture  as so  amended by this
Supplemental Indenture.

          Section 2.03 Parties Bound. This  Supplemental  Indenture shall form a
                       -------------
part of the Indenture for all purposes, and every holder of the Notes heretofore
or  hereafter  authenticated  and  delivered  shall  be bound  hereby.  Upon the
execution  of  this  Supplemental   Indenture,   the  Indenture  and  the  Notes
theretofore issued shall be deemed to be modified and amended in accordance with
this  Supplemental  Indenture and the respective  rights,  limitation of rights,
obligations,  duties and  immunities  under the Indenture of the Company and the
Trustee and the Holders of the Notes shall  thereafter be determined,  exercised
and  enforced  thereunder  subject in all  respects  to such  modifications  and
amendments,  and all the terms and  conditions  of this  Supplemental  Indenture
shall be and be deemed to be part of the terms and  conditions  of the Indenture
and the Notes theretofore issued for any and all purposes.

          Section 2.04  Successors and Assignees.  All agreements of the Company
                        ------------------------
and the Trustee in this  Supplemental  Indenture,  the  Indenture  and the Notes
shall bind their


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respective successors and assigns. This Supplemental  Indenture shall be binding
upon each Holder of Notes and their respective successors and assigns.

          Section 2.05 Counterparts. This Supplemental Indenture may be executed
                       ------------
in any number of counterparts, each of which when so executed shall be deemed to
be an original,  and all of such counterparts shall together  constitute one and
the same instrument.

          Section 2.06 Severability.  In case any provision in this Supplemental
                       ------------
Indenture shall be invalid, illegal or unenforceable, the validity, legality and
enforceability  of the remaining  provisions shall not in any way be affected or
impaired thereby.

          Section  2.07  Headings.  The headings of the Articles and Sections of
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this Supplemental Indenture have been inserted for convenience of reference only
and are not to be considered part of this Supplemental Indenture and shall in no
way  modify or  restrict  any of the terms or  provisions  of this  Supplemental
Indenture.

          Section  2.08  Effective  Date of this  Supplemental  Indenture.  This
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Supplemental  Indenture and the amendments to Sections 1.01,  4.06,  4.07, 4.08,
4.09, 4.10, 4.11, 4.12, 4.13, 4.14, 4.15, 4.16, 4.17, 4.18, 6.01, 6.02, 6.04 and
11.04 and Article V shall be effective pursuant to Section 9.03 of the Indenture
immediately  upon  execution by the Company and delivery to and execution by the
Trustee of this Supplemental Indenture.

          Section 2.09 Trustee Disclaimer.  The Trustee accepts the amendment of
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the Indenture  effected by this  Supplemental  Indenture as hereby amended,  but
only upon the terms and  conditions  set forth in the  Indenture,  including the
terms and conditions defining and limiting the liabilities and  responsibilities
of the  Trustee  in the  performance  of its duties  and  obligations  under the
Indenture, as hereby amended.  Without limiting the generality of the foregoing,
the  Trustee  shall not be  responsible  in any  manner  whatsoever  for or with
respect to any of the  recitals or  statements  contained  herein,  all of which
recitals or statements are made solely by the Company, or for or with respect to
(i) the validity, efficacy, or sufficiency of this Supplemental Indenture or any
of the terms or provisions hereof, (ii) the proper  authorization  hereof by the
Company by corporate  action or otherwise,  or (iii) the due execution hereof by
the Company and the Trustee  makes no  representation  with  respect to any such
matters.

          Section 2.10  Governing  Law.  This  Supplemental  Indenture  shall be
                        --------------
governed by and construed in  accordance  with the internal laws of the State of
New York without giving effect to principles of conflicts of laws.


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     IN WITNESS  WHEREOF,  the parties  hereto  have  caused  this  Supplemental
Indenture to be duly executed as of the date first above written.



                                       AZTECA HOLDINGS, S.A. DE C.V.



                                       By: /s/ Luis Ontiveros
                                           --------------------------------
                                       Name:    Luis Ontiveros
                                       Title:   Attorney-in-Fact



                                       By: /s/ Othon Frias
                                           --------------------------------
                                       Name:    Othon Frias
                                       Title:   Attorney-in-Fact


                                       THE BANK OF NEW YORK,
                                           as Trustee



                                       By: /s/ Miguel Barrios
                                           --------------------------------
                                       Name:    Miguel Barrios
                                       Title:   Representante Legal