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                                                                     EXHIBIT 4.2

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                              GLOBESPANVIRATA, INC

                                       and

                              THE BANK OF NEW YORK
             (successor to UNITED STATES TRUST COMPANY OF NEW YORK),
                                   as Trustee

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                          First Supplemental Indenture

                          Dated as of February 27, 2004

                                       To

                                    Indenture

                            Dated as of May 11, 2001

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        Providing for adjustments to the Conversion Price of the 5 -1/4%
        Convertible Subordinated Notes due 2006 of GlobespanVirata, Inc.

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            FIRST SUPPLEMENTAL INDENTURE dated as of February 27, 2004 by and
between GLOBESPANVIRATA, INC. f/k/a GLOBESPAN, INC., a Delaware corporation (the
"Company"), having its principal office at 100 Schulz Drive, Red Bank, New
Jersey 07701, and THE BANK OF NEW YORK (successor to UNITED STATES TRUST COMPANY
OF NEW YORK), as Trustee (the "Trustee"), having its principal corporate office
at 101 Barclay Street, 8W, New York, New York 10286.

                              W I T N E S S E T H:

            WHEREAS, the Company executed and delivered to the Trustee an
Indenture dated as of May 11, 2001 (the "Indenture"), pursuant to which the
Company issued $130,000,000 aggregate principal amount of its 5 -1/4%
Convertible Subordinated Notes due May 15, 2006 (the "Notes"), all of which
remain outstanding as of the date hereof;

            WHEREAS, the Board of Directors of the Company has determined that
it is in the best interests of the Company and its shareowners for Concentric
Sub, Inc. ("Concentric Sub"), a Delaware corporation and a wholly-owned
subsidiary of Conexant Systems, Inc., a Delaware corporation ("Conexant"), to
merge with and into the Company, with the Company surviving as a wholly-owned
subsidiary of Conexant (the "Merger");

            WHEREAS, pursuant to the Agreement and Plan of Reorganization dated
as of November 3, 2003, as amended as of January 15, 2004 (the "Merger
Agreement"), by and among Conexant, Concentric Sub and the Company, in the
Merger, Conexant will issue 1.198 shares of its Common Stock, par value $.01 per
share (together with the associated preferred share purchase rights, the
"Conexant Common Stock"), in exchange for each outstanding share of Common
Stock, par value $.001 per share, of the Company (the "Company Common Stock")
and cash in lieu of fractional shares;

            WHEREAS, Section 12.01 of the Indenture provides that, subject to
the provisions of Section 12.02 of the Indenture, the Company may consolidate or
merge with or into any other corporation or may sell, convey or lease all or
substantially all of the property of the Company and its consolidated
subsidiaries, taken as a whole, to any other corporation, authorized to acquire
and operate the same and that shall be organized under the laws of the United
States of America, any state thereof or the District of Columbia;

            WHEREAS, Section 15.06 of the Indenture provides that in the event
of any merger of the Company with any other corporation as a result of which
holders of Company Common Stock shall be entitled to receive stock, other
securities or other assets (including cash) with respect to or in exchange for
such Company Common Stock, the Company shall execute with the Trustee a
supplemental indenture providing that the

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Notes shall be convertible into the kind and amount of shares of stock, other
securities or other property or assets (including cash) receivable upon such
merger by a holder of a number of shares of Company Common Stock issuable upon
conversion of such Notes immediately prior to such merger; and

            WHEREAS, all things necessary to make this First Supplemental
Indenture a valid indenture supplemental to the Indenture have been done;

            NOW, THEREFORE, for and in consideration of the premises and of the
mutual covenants herein contained, it is hereby agreed as follows:

                                    ARTICLE I
                                   DEFINITIONS

            Section 1.1. Definitions. Each capitalized term used herein and not
otherwise defined herein shall have the meaning attributed thereto in the
Indenture.

                                   ARTICLE II
                         ADJUSTMENT OF CONVERSION PRICE

            Section 2.1. Adjustment. Pursuant to Section 15.06 of the Indenture,
from and after the Merger, the Notes shall be convertible into shares of
Conexant Common Stock and the Conversion Price shall be adjusted so that the
same shall equal the price determined by dividing the Conversion Price in effect
immediately prior to the Merger by 1.198, the exchange ratio in the Merger.
Thereafter, the term "Common Stock" in the Indenture shall refer to Conexant
Common Stock.

                                  ARTICLE III
                             CONCERNING THE TRUSTEE

            Section 3.1. Responsibility for Recitals, etc. The Trustee assumes
no responsibility for the correctness of the recitals herein contained, which
shall be taken as the statements of the Company. The Trustee makes no
representation and shall have no responsibility as to the validity or
sufficiency of this First Supplemental Indenture.

                                   ARTICLE IV
                                  MISCELLANEOUS

            Section 4.1. Effectiveness. Notwithstanding anything contained in
this First Supplemental Indenture to the contrary, none of the provisions of
this First

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Supplemental Indenture will become effective or be of any force or effect until
the Effective Time (as defined in the Merger Agreement) has occurred.

            Section 4.2. Execution of First Supplemental Indenture. This First
Supplemental Indenture is executed and shall be construed as an indenture
supplemental to the Indenture and, as provided in the Indenture, this First
Supplemental Indenture forms a part thereof. The Indenture, as supplemented and
amended by this First Supplemental Indenture, is in all respects hereby adopted,
ratified and confirmed.

            Section 4.3. Governing Law. This First Supplemental Indenture shall
be deemed to be a contract made under the laws of the State of New York, and for
all purposes shall be construed in accordance with the laws of the State of New
York.

            Section 4.4. Execution in Counterparts. This First Supplemental
Indenture may be executed in any number of counterparts, each of which shall be
an original but such counterparts shall together constitute but one and the same
instrument.

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

                                       GLOBESPANVIRATA, INC.

                                       By: /s/ Armando Geday
                                           -------------------------------------
                                           Name:  Armando Geday
                                           Title: President and Chief Executive
                                           Officer

                                       THE BANK OF NEW YORK, as Trustee

                                       By: /s/ Sirojni Dindial
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                                           Name:  Sirojni Dindial
                                           Title: Assistant Vice President

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