QuickLinks -- Click here to rapidly navigate through this document

Exhibit 10.25

AMENDMENT TO SEVERANCE PROTECTION AGREEMENT

        This Amendment to the Severance Protection Agreement entered into as of
December 21, 1999, by and between General Instrument Corporation, a Delaware
Corporation (the "Corporation"), and Thomas J. Lynch (the "Executive") (such
agreement, the "Severance Protection Agreement") is among the Corporation, the
Executive, and Motorola, Inc. ("Motorola") and is dated as of December 21, 1999.

        WHEREAS, the Corporation, Motorola and Lucerne Acquisition Corp. have
entered into an Agreement and Plan of Merger dated as of September 14, 1999
(such agreement, as amended from time to time, the "Merger Agreement"), pursuant
to which the Corporation will become a wholly owned subsidiary of Motorola in a
merger (the "Merger"); and

        WHEREAS, the Executive is employed by the Corporation; and

        WHEREAS, the Corporation and Motorola wish to ensure that they will
continue to receive the benefit of the Executive's services following the
Merger, and to provide for the terms and conditions of the Executive's
employment following the Merger, and the Executive is willing to remain so
employed on such terms and conditions;

        NOW, THEREFORE, the parties hereto, intending to be legally bound,
hereby agree as follows:

        1.    Retention Program.    (a) As soon as practical after the Effective
Time (as defined in the Merger Agreement), but in no event later than ten
business days thereafter, Motorola shall grant the Executive stock options with
respect to 65,000 shares (the "Closing Options") with an exercise price equal to
the fair market value of the underlying shares on the date of grant, and 7,500
shares of restricted stock (the "Closing Shares"), in each case pursuant to the
Motorola Incentive Plan of 1998 (the "Motorola Incentive Plan") subject to
appropriate adjustment as to the number of shares if an event described in
Section 3.3 of the Motorola Incentive Plan (an "Adjustment Event") occurs on or
before the date of grant. The Closing Options shall be scheduled to vest in four
equal installments on each of the first four anniversaries of the date of grant,
and all of the Closing Shares shall vest on the second anniversary of the day on
which the Effective Time occurs, in each case subject to the Executive's
continued employment until the date of vesting, and the Closing Options and the
Closing Shares shall otherwise be subject to the terms and conditions of the
Motorola Incentive Plan.

        (a)  At the time when Motorola makes its annual stock option grants to
executives for the fiscal year following the fiscal year in which the Effective
Time occurs, Motorola shall grant the Executive stock options with respect to
15,000 shares pursuant to the Motorola Incentive Plan or any successor thereto,
subject to appropriate adjustment as to the number of shares if an Adjustment
Event occurs on or before the date of grant. Such options shall be scheduled to
vest in four equal installments on each of the first four anniversaries of the
date of grant, subject to the Executive's continued employment until the date of
vesting, shall have an exercise price equal to the fair market value of the
underlying shares on the date of grant, and shall otherwise be subject to the
terms and conditions of the Motorola Incentive Plan or such successor.

        (b)  If the Executive remains employed by Motorola or one of its
Subsidiaries (including without limitation the Corporation) from the date on
which the Effective Time occurs through the second anniversary thereof, or
sooner terminates employment as a result of death or Disability, the Executive
shall receive a one-time Retention Cash Bonus equal to $385,000.

        2.    Change in Control; Term.    It is acknowledged and agreed that the
approval of the Merger by the Corporation's stockholders will be a "Change in
Control" as defined in Section 13.7 of the Severance Protection Agreement, and
that if such approval occurs, no subsequent event shall be deemed to be a Change
in Control for purposes of the Severance Protection Agreement. As a result, if
such approval occurs, then notwithstanding any provision of the Severance
Protection Agreement: (i) the "Term" shall mean the period ending on the second
anniversary of the date on which the Effective Time occurs, and shall not be
further renewed or extended except by written agreement among the parties
hereto; and (ii) each reference in the Severance Protection Agreement to a
Change in Control shall be deemed to refer to such stockholder approval and to
no other event.

        3.    Employment Transfer.    It is acknowledged and agreed that the
Executive may, at and/or from time to time after the Effective Time, be
transferred to the employment of Motorola or a Subsidiary of Motorola, and that
in connection with any such transfer, the Corporation may assign to the
employing entity its rights, and cause the employing entity to assume its
obligations, under the Severance Protection Agreement and this Amendment. In
such event, references to the Corporation in the Severance Protection Agreement
and this Amendment shall be deemed to refer to such employing entity.

--------------------------------------------------------------------------------

        4.    Amendments to Severance Protection Agreement.    The following
amendments to the Severance Protection Agreement shall be effective as of the
Effective Time.

        (a)    Termination Benefits.    Notwithstanding Section 2(b)(3) of the
Severance Protection Agreement, the requirement of that clause that certain
specified life insurance, disability, medical, dental and hospitalization
coverages and benefits be provided shall be satisfied if the Corporation or
Motorola provides the Executive and his dependents and beneficiaries with such
coverages and benefits on the terms and conditions (including employee
contributions, deductibles and the like) on which such coverages and benefits
are provided to active employees of the Corporation or Motorola during the
18-month period required by that clause (and subject to reduction as provided in
that clause); provided, that the Executive shall not be entitled to duplicate
benefits under plans of the Corporation and Motorola.

        (b)    Coordination with Motorola Change of Control
Agreement.    Section 2(g) of the Severance Protection Agreement is hereby
amended by adding a new sentence at the end thereof, reading in its entirety as
follows: "Notwithstanding any other provision of this Agreement, if the
Executive hereafter becomes a party to any agreement with Motorola or any of its
Subsidiaries providing for severance pay and/or benefits upon a termination of
employment upon, after or in connection with a change of control (however
defined), then the severance pay and benefits due under such agreement shall
first be determined as if the Executive were not a party to this Agreement (the
"Subsequent Severance"), and the payments and benefits to which the Executive
would otherwise be entitled pursuant to this Section 2 shall be offset by the
Subsequent Severance so that there is no duplication thereof."

        (c)    Good Reason.    The following provisions shall apply
notwithstanding Section 13.10 of the Severance Protection Agreement:

          (i)  It is acknowledged and agreed that following the Effective Time,
the Executive will serve as Corporate Vice President and General Manager, SBNS,
Broadband Communications Sector, responsible for the strategic, tactical and
operational leadership of the SBNS business unit of the Broadband Communications
Sector. The responsibilities are focused on ensuring that the unit meets or
exceeds its operational goals in a manner consistent with the overall business
plan of the sector, Communications Enterprise and Motorola. The position reports
to the Executive Vice President and President of the Broadband Communications
Sector, and that so long as the Executive remains in such position or its
equivalent in terms of scope of authority, there shall not be deemed to have
been a change described in Section 13.10(a)(l) of the Severance Protection
Agreement, notwithstanding any transfer of the Executive's employment described
in Section 3 of this Amendment;

        (ii)  Section 13.10(a)(5) of the Severance Protection Agreement is
hereby amended to read in its entirety as follows:

        (5)  the failure by Motorola to cause the Executive to be eligible to
participate in the Incentive Plan and/or Motorola's compensation, employee
benefit and perquisite plans and programs (other than severance plans and
programs) on a basis no less favorable, in the aggregate, than that for
comparable Motorola executives; and

        (iii)  The Executive expressly acknowledges and agrees that the
Corporation has complied with the requirements of Section 9 of the Severance
Protection Agreement in connection with the Merger.

        (d)    Incentive Plan.    Section 13.11 of the Severance Protection
Agreement is hereby amended by adding an additional sentence at the end thereof,
reading in its entirety as follows: "Notwithstanding the foregoing, beginning
with the fiscal year 2001, the Incentive Plan shall mean the short-term
incentive compensation program of Motorola in which the Executive participates."

        (e)    Notices.    Whenever a notice is given pursuant to the Severance
Protection Agreement to the Corporation, a copy of such notice shall be given
to:

Motorola, Inc.
1303 East Algonquin Road
Schaumburg, Illinois 60196
Telecopier No.: (847) 576-3628
Attention: General Counsel

2

--------------------------------------------------------------------------------

or to such other names or addresses as Motorola shall designate by notice
pursuant to Section 5 of the Severance Protection Agreement.

        (f)    Defined Terms.    The term "Subsidiary" as used herein means any
entity in an unbroken chain of entities beginning with Motorola and ending with
such entity, with each entity in such chain, beginning with Motorola, and other
than the last entity in the chain, owning an equity interest representing at
least fifty percent of the voting power or value of the next entity in such
chain. Capitalized terms used and not defined in this Amendment shall have the
meanings given to them in the Severance Protection Agreement.

        5.    This Amendment, together with the Severance Protection Agreement
as amended hereby, set forth the entire understanding among the parties hereto
with respect to the subject matter hereto. Without limiting the generality of
the foregoing, this Amendment supersedes the memorandum to the Executive from
Keith Bane and Merle Gilmore dated October 8, 1999.

        6.    This Amendment shall be null and void and of no further effect if
the Merger Agreement is terminated without consummation of the Merger.

        IN WITNESS WHEREOF, the undersigned, intending to be legally bound, have
executed this Agreement as of the date first above written.

  GENERAL INSTRUMENT CORPORATION
 
By:
 
/s/  SCOTT CRUM      

--------------------------------------------------------------------------------

 
MOTOROLA, INC.
 
By:
 
/s/  MERLE GILMORE      

--------------------------------------------------------------------------------

 
By:
 
/s/  THOMAS J. LYNCH      

--------------------------------------------------------------------------------

Thomas J. Lynch

3

--------------------------------------------------------------------------------

QuickLinks

Exhibit 10.25