UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13G



                    Under the Securities Exchange Act of 1934

                               (Amendment No. 1 )*

                               BSquare Corporation
        ----------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
        ----------------------------------------------------------------
                         (Title of Class of Securities)


                                    11776U102
                  -------------------------------------------
                                 (CUSIP Number)



                                December 31, 2002
        ----------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

                                  [x] Rule 13d-1(b)
                                  [ ] Rule 13d-1(c)
                                  [ ] Rule 13d-1(d)



*    The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                               Page 1 of 10 pages

CUSIP No.    11776U102                 13G                    Page 2 of 10 Pages

--------------------------------------------------------------------------------
 1   NAME OF REPORTING PERSON
     S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

        Liberty Wanger Asset Management, L.P.  36-3820584

--------------------------------------------------------------------------------
 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

        Not Applicable                                                   (a) / /

                                                                         (b) / /

--------------------------------------------------------------------------------
 3   SEC USE ONLY

--------------------------------------------------------------------------------
 4   CITIZENSHIP OR PLACE OF ORGANIZATION

        Delaware

--------------------------------------------------------------------------------
    NUMBER OF       5  SOLE VOTING POWER

     SHARES              None
                    ------------------------------------------------------------
  BENEFICIALLY      6  SHARED VOTING POWER

    OWNED BY             3,500,000

      EACH          ------------------------------------------------------------
                    7  SOLE DISPOSITIVE POWER
    REPORTING
                         None
   PERSON WITH
                    ------------------------------------------------------------
                    8  SHARED DISPOSITIVE POWER

                         3,500,000

--------------------------------------------------------------------------------
  9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

        3,500,000

--------------------------------------------------------------------------------
 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
     SHARES*                                                                 / /

        Not Applicable

--------------------------------------------------------------------------------
 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

        9.5%

--------------------------------------------------------------------------------
 12  TYPE OF REPORTING PERSON*

        IA
--------------------------------------------------------------------------------

CUSIP No.    11776U102                 13G                    Page 3 of 10 Pages

--------------------------------------------------------------------------------
 1   NAME OF REPORTING PERSON
     S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

        WAM Acquisition GP, Inc.

--------------------------------------------------------------------------------
 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

        Not Applicable                                                   (a) / /

                                                                         (b) / /

--------------------------------------------------------------------------------
 3   SEC USE ONLY

--------------------------------------------------------------------------------
 4   CITIZENSHIP OR PLACE OF ORGANIZATION

        Delaware

--------------------------------------------------------------------------------
    NUMBER OF       5  SOLE VOTING POWER

     SHARES              None
                    ------------------------------------------------------------
  BENEFICIALLY      6  SHARED VOTING POWER

    OWNED BY             3,500,000

      EACH          ------------------------------------------------------------
                    7  SOLE DISPOSITIVE POWER
    REPORTING
                         None
   PERSON WITH
                    ------------------------------------------------------------
                    8  SHARED DISPOSITIVE POWER

                         3,500,000

--------------------------------------------------------------------------------
  9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

        3,500,000

--------------------------------------------------------------------------------
 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
     SHARES*                                                                 / /

        Not Applicable

--------------------------------------------------------------------------------
 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

        9.5%

--------------------------------------------------------------------------------
 12  TYPE OF REPORTING PERSON*

        CO
--------------------------------------------------------------------------------


CUSIP No.    11776U102                 13G                    Page 4 of 10 Pages

--------------------------------------------------------------------------------
 1   NAME OF REPORTING PERSON
     S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

        Liberty Acorn Trust

--------------------------------------------------------------------------------
 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

        Not Applicable                                                   (a) / /

                                                                         (b) / /

--------------------------------------------------------------------------------
 3   SEC USE ONLY

--------------------------------------------------------------------------------
 4   CITIZENSHIP OR PLACE OF ORGANIZATION

        Massachusetts

--------------------------------------------------------------------------------
    NUMBER OF       5  SOLE VOTING POWER

     SHARES              None
                    ------------------------------------------------------------
  BENEFICIALLY      6  SHARED VOTING POWER

    OWNED BY             3,300,000

      EACH          ------------------------------------------------------------
                    7  SOLE DISPOSITIVE POWER
    REPORTING
                         None
   PERSON WITH
                    ------------------------------------------------------------
                    8  SHARED DISPOSITIVE POWER

                         3,300,000

--------------------------------------------------------------------------------
  9  AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

        3,300,000

--------------------------------------------------------------------------------
 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
     SHARES*                                                                 / /

        Not Applicable

--------------------------------------------------------------------------------
 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

        9.0%

--------------------------------------------------------------------------------
 12  TYPE OF REPORTING PERSON*

        IV
--------------------------------------------------------------------------------


Item 1(a)         Name of Issuer:

                        BSquare Corporation


Item 1(b)         Address of Issuer's Principal Executive Offices:

                        3150 139th Avenue SE
                        Suite 500
                        Bellevue, WA 98005


Item 2(a)         Name of Person Filing:

                        Liberty Wanger Asset Management, L.P. ("WAM")
                        WAM Acquisition GP, Inc., the general partner of WAM
                           ("WAM GP")
                        Liberty Acorn Trust ("Acorn")



Item 2(b)         Address of Principal Business Office:

                        WAM, WAM GP and Acorn are all located at:

                        227 West Monroe Street, Suite 3000
                        Chicago, Illinois  60606


Item 2(c)         Citizenship:

                        WAM is a Delaware limited partnership; WAM GP is a
                        Delaware corporation; and Acorn is a Massachusetts
                        business trust.


Item 2(d)         Title of Class of Securities:

                        Common Stock


Item 2(e)         CUSIP Number:

                        11776U102


Item 3            Type of Person:

                        (d)   Acorn is an Investment Company under section 8 of
                              the Investment Company Act.

                        (e)   WAM is an Investment Adviser registered under
                              section 203 of the Investment Advisers Act of
                              1940; WAM GP is the General Partner of the
                              Investment Adviser.


                               Page 5 of 10 pages

Item 4            Ownership (at December 31, 2002):

                        (a)   Amount owned "beneficially" within the meaning of
                              rule 13d-3:

                              3,500,000

                        (b)   Percent of class:

                              9.5 % (based on 36,860,280 shares outstanding as
                              of November 1, 2002).

                        (c)   Number of shares as to which such person has:

                              (i)       sole power to vote or to direct the
                                        vote: none

                              (ii)      shared power to vote or to direct the
                                        vote: 3,500,000

                              (iii)     sole power to dispose or to direct the
                                        disposition of: none

                              (iv)      shared power to dispose or to direct
                                        disposition of: 3,500,000


Item 5            Ownership of Five Percent or Less of a Class:

                        Not Applicable


Item 6            Ownership of More than Five Percent on Behalf of Another
                  Person:

                        The shares reported herein have been acquired on behalf
                        of discretionary clients of WAM, including Acorn.
                        Persons other than WAM and WAM GP are entitled to
                        receive all dividends from, and proceeds from the sale
                        of, those shares. Acorn is the only such person known to
                        be entitled to all dividends from, and all proceeds from
                        the sale of, shares reported herein to the extent of
                        more than 5% of the class.


Item 7            Identification and Classification of the Subsidiary Which
                  Acquired the Security Being Reported on by the Parent Holding
                  Company:

                        Not Applicable


Item 8            Identification and Classification of Members of the Group:

                        Not Applicable


Item 9            Notice of Dissolution of Group:

                        Not Applicable


                               Page 6 of 10 pages

Item 10           Certification:

                        By signing below I certify that, to the best of my
                  knowledge and belief, the securities referred to above were
                  acquired and are held in the ordinary course of business and
                  were not acquired and are not held for the purpose of or with
                  the effect of changing or influencing the control of the
                  issuer of the securities and were not acquired and are not
                  held in connection with or as a participant in any transaction
                  having that purpose or effect.


                               Page 7 of 10 pages

                                      Signature

      After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.


Date:  February 4, 2003


                  The undersigned corporation, on the date above written, agrees
                  and consents to the joint filing on its behalf of this
                  Schedule 13G in connection with its beneficial ownership of
                  the security reported herein.


                                        WAM Acquisition GP, Inc.
                                          for itself and as general partner of
                                          LIBERTY WANGER ASSET MANAGEMENT, L.P.



                                        By:  /s/ Bruce H. Lauer
                                             ---------------------------------
                                             Bruce H. Lauer
                                             Senior Vice President and Secretary




                  The undersigned corporation, on the date above written, agrees
                  and consents to the joint filing on its behalf of this
                  Schedule 13G in connection with its beneficial ownership of
                  the security reported herein.


                                        LIBERTY ACORN TRUST



                                        By:  /s/ Bruce H. Lauer
                                             ---------------------------------
                                             Bruce H. Lauer
                                             Vice President, Treasurer and
                                             Secretary


                               Page 8 of 10 pages

                                    Exhibit Index

Exhibit 1                 Joint Filing Agreement dated as of February 4, 2003
                          by and among Liberty Wanger Asset Management, L.P.,
                          WAM Acquisition GP, Inc. and Liberty Acorn Trust


                               Page 9 of 10 pages