Exhibit 10.4.3
 Am Contract No. 750-33576-2001
Amendment # 6
 Amendment No. 6 to the
Master Software License and Distribution Agreement
(Contract No. 220-00-0134) between
Cellco Partnership, a Delaware general partnership d/b/a Verizon Wireless
and
Smith Micro Software, Inc.
 This Amendment No. 6 (Amendment)
    1.
    
    This Amendment is an integral part of the Agreement. The terms used herein which are
defined or specified in the Agreement shall have the meanings set forth in the Agreement.
If there are any inconsistencies between a specific term or condition of this Amendment and
a specific term or condition of the Agreement, the specific term or condition of this
Amendment shall control.2.
    
    The following definitions shall be changed or added to Section 1.1 (Definitions) as set
forth below:
    1






---



##### 



2






---



##### 



k.
    
    Related Services means (1) those services such as technical
support, training, customization and adaptation and other services provided for
herein which SMSI will provide to Verizon Wireless hereunder. Those Related
Services which will be provided by SMSI and the charges therefore, if any, shall
be as specified on the Schedules A, A-1, A-2, A-3, A-4, A-6, A-7, A-8, B and E
attached hereto, and incorporated herein by reference.
  m.
    
    Software refers to the computer program and applications,
available hereunder as described in Schedules A, A-l, A-2, A-3, A-4, A-6, A-7 and
A-8 and includes all related documentation and manuals.
 3.
    
    Section 1.2 Scope shall be deleted in its entirely and replaced with the following:1.2 Scope. SMSI shall provide to Verizon Wireless the Software, Kits and Related Services
as described in Orders Verizon Wireless may from time to time place hereunder. It is
expressly understood and agreed that this Agreement is intended to establish uniform and
consistent terms and conditions for any such Orders and that Verizon Wireless is not
obligated to place any Orders with SMSI. It is further expressly understood and agreed
that this Agreement does not limit, in any way, the right of Verizon Wireless to contract
with any other parties for the procurement of comparable products, software and/or
services, subject to any intellectual property rights of SMSI in and to any SMSI Work
Product.4.
    
    Section 2.1.13 of the Agreement shall be deleted in its entirety and replaced with
the following:2.1.13 SMSI hereby grants Verizon Wireless the right to sublicense, reproduce, distribute
and market current and future versions of QuickAccess to manufacturers and distributors of
Embedded Products and to grant to such parties the right to reproduce, market and
distribute QuickAccess for use with its Embedded Product.5.
    
    Section 2.1.14 of the Agreement shall be deleted in its entirety and replaced with
the following:2.1.14 SMSI grants to Verizon Wireless a right to sublicense QuickAccess to manufacturers
and distributors of Embedded Products to permit them to create a Compact Disc containing
QuickAccess solely for the purpose of enabling such parties end-users of the Embedded
Product to reinstall QuickAccess, among other products, in the event of a system failure or
hard drive failure on the end-users Embedded Product (Recovery CD). The Recovery CD may
be distributed after Termination.
  3






---



##### 



6.
    
    Section 3.2 a of the Agreement (which is preceded by the introductory clause,
This Agreement may be terminated, by written notice only, as follows:) shall be deleted
in its entirety and replaced with the following:a. By Verizon Wireless, at least [****] prior to the expiration of any Term or
Renewal Term, or by SMSI at least [****] prior to the expiration of any Term or
Renewal Term, with such termination in either case being effective as of the end of such
Term or Renewal Term. Verizon Wireless shall have the right to place Orders up to and
including the effective date of such termination, and termination of this Agreement
pursuant to this subsection a shall not affect any Outstanding Order as of the effective
date of such termination.7.
    
    Section 3.3.2 of the Agreement shall be deleted in its entirety and replaced with
the following:3.3.2 Provided Verizon Wireless continues to pay the license fees to acquire new licenses
to use the Unified Client or the Combination Client, QuickAccess, V CAST Music Essentials
Manager and the QuickLink® Mobile Phonebook software, SMSI shall grant to Verizon
Wireless, subject to the terms and conditions of this Agreement, at Verizon Wireless
option, [****], the irrevocable, non-exclusive, non-transferable (except to a
parent or Affiliate of Verizon Wireless), limited right to manufacture or have
manufactured, enhance or have enhanced, market and distribute the Final Software and the
QuickLink® Mobile Phonebook software to distributors, resellers, Original Equipment
Manufacturer (OEM) customers of Verizon Wireless, subscribers of Verizon Wireless and
end-users.
 3.3.2.1
    
    In the event that SMSI files for bankruptcy or ceases to do business, or
Termination under Section 3.3 of this Agreement, SMSI shall provide to Verizon
Wireless, subject to the terms and conditions of this Agreement, the source
codes, which will be disclosed to Verizon for use solely in order to perform
under this Agreement and for use of the Software as permitted thereunder, but
not to disclose, make derivative works, transfer, sell or assign to others, as
well as all operating and design documentation, training materials and any
other necessary information, and grant to Verizon Wireless, at Verizon
Wireless option, for five (5) years, an irrevocable, non-exclusive,
non-transferable (except to a parent or subsidiary of Verizon Wireless)
limited license to maintain, have maintained and enhance or have enhanced all
SMSI Final Software source codes necessary to support all Software created for
Verizon Wireless under this Agreement. At the expiration of such time period,
Verizon Wireless shall discontinue all of use of such source codes and any
copies thereof, and shall deliver to SMSI or destroy, at SMSIs option, all
copies of such source codes, including all documentation and related materials
furnished by SMSI.
 8.
    
    Section 5.1 (License Fees) shall be deleted in its entirety and replaced with the
following:
  4






---



##### 



License Fees.
 ®
     5






---



##### 



9.
    
    Section 5.5 Risk of Loss shall be deleted in its entirety and replaced with the following:5.5 Risk of Loss. Verizon Wireless shall bear the risk of loss or damage to the
Software during shipment to the end-user. If Verizon Wireless designated freight carrier
is utilized, or in the event Verizon Wireless shall instruct SMSI to expedite a shipment,
Verizon Wireless shall bear the risk of loss of or damage to the Software while in transit
to Verizon Wireless or to third parties purchasing on behalf of Verizon Wireless.10.
    
    Section 7.3 shall be added to the Agreement, as follows:
  11.
    
    Sections 8.2 and 8.3 shall be deleted in their entirety and replaced with the following:
   6






---



##### 



7






---



##### 



Ownership.
  SMSI Proprietary Technology.
  8






---



##### 



SMSI Software.
  Assignment and License Grant
    9






---



##### 



Source Code.
 Work for Hire.
       10






---



##### 



Per Unit Price (License)
 1.
    
    When shipped with VZAccess Manager as part of the Mobile Office
Kits and not as a stand-alone product: [****]2.
    
    When shipped as a stand-alone product: [****]
  11






---



##### 



12






---



##### 



13






---



##### 



14






---



##### 



15






---



##### 



IN WITNESS WHEREOF, the Parties hereto have caused this Amendment to be executed by
their duly authorized officers or representatives.
 CELLCO PARTNERSHIP
    
    
    
    SMITH MICROSOFTWARE, INC.d/b/a Verizon
WirelessBy: 
Name:
    
    /s/ James Straight

James Straight
    
    
    
    By:
Name:
    
    /s/ William W. Smith, Jr.

William W. Smith, Jr.Title:
    
    VP Data
    
    
    
    Title:
    
    President/CEODate:
    
    1 Nov. 06
    
    
    
    Date:
    
    Oct. 31, 2006
  16