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                                                                   EXHIBIT 10.27


                          AMENDMENT TO RIGHTS AGREEMENT


         This AMENDMENT, dated as of July 29, 1999, is between XIONICS DOCUMENT
TECHNOLOGIES, INC., a Delaware corporation (the "COMPANY"), and BANKBOSTON,
N.A., as rights agent (the "RIGHTS AGENT").

                                    RECITALS

         A.       The Company and the Rights Agent are parties to a Rights
Agreement, dated as of April 15, 1998 (the "RIGHTS AGREEMENT").

         B.       The Company, Oak Technology, Inc. ("OAK"), and a wholly-owned
subsidiary of Oak ("MERGER SUB") have entered into an Agreement and Plan of
Merger (the "MERGER AGREEMENT"), pursuant to which Sub will merge with the
Company (the "MERGER") and the Company will become a wholly-owned subsidiary of
Oak. The Board of Directors of the Company has approved the Merger Agreement and
the Oak.

         C.       Pursuant to Section 28 of the Rights Agreement, the Board of
Directors of the Company has determined that an amendment to the Rights
Agreement as set forth herein is necessary and desirable in connection with the
foregoing and the Company and the Rights Agent desire to evidence such amendment
in writing.

         Accordingly, the parties agree as follows:

         1.       AMENDMENTS OF SECTION 1.

         (a)      The definition of "Acquiring Person" set forth in Section 1 of
the Rights Agreement is amended to add the following sentence at the end
thereof:

                  "Notwithstanding anything in this Rights Agreement to the
                  contrary, neither Oak Technology, Inc. ("OAK") nor any of its
                  existing or future Affiliates or Associates shall be deemed to
                  be an Acquiring Person solely by virtue of (i) the execution
                  of the Agreement and Plan of Merger, dated as of July 29,
                  1999, by and among the Company, Oak and Xionics Acquisition
                  Corporation ("MERGER SUB") (as the same may be amended from
                  time to time, the "MERGER AGREEMENT"), pursuant to which
                  Merger Sub will be merged with the Company (the "MERGER"), and
                  the Company shall become a wholly-owned subsidiary of Oak,
                  (ii) the acquisition of Common Shares pursuant to the Merger
                  Agreement or the consummation of the Merger, or (iii) the
                  consummation of the other transactions contemplated by the
                  Merger Agreement."

         (b)      The definition of "Triggering Event" set forth in Section 1 of
the Rights Agreement is amended to add the following proviso at the end thereof:

                  "; provided, however, that no Triggering Event shall result
                  solely by virtue of (i) the execution of the Merger Agreement,
                  (ii) the acquisition of Common Shares pursuant to the Merger
                  Agreement or the consummation of the Merger, or (iii) the
                  consummation of the other transactions contemplated by the
                  Merger Agreement."


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         2.       AMENDMENT OF SECTION 3(a). Section 3(a) of the Rights
Agreement is amended to add the following sentence at the end thereof:

                  "Notwithstanding anything in this Rights Agreement to the
                  contrary, a Distribution Date shall not be deemed to have
                  occurred solely by virtue of (i) the execution of the Merger
                  Agreement, (ii) the acquisition of Common Shares pursuant to
                  the Merger Agreement or the consummation of the Merger, or
                  (iii) the consummation of the other transactions contemplated
                  by the Merger Agreement."

         3.       AMENDMENT OF SECTION 7(a). Section 7(a) of the Rights
Agreement is amended to add the following sentence at the end thereof:

                  "Notwithstanding anything in this Rights Agreement to the
                  contrary, neither (i) the execution of the Merger Agreement;
                  (ii) the acquisition of Common Shares pursuant to the Merger
                  Agreement or the consummation of the Merger; nor (iii) the
                  consummation of the other transactions contemplated in the
                  Merger Agreement, shall be deemed to be events that cause the
                  Rights to become exercisable pursuant to the provisions of
                  this Section 7 or otherwise."

         4.       AMENDMENT OF SECTION 11. Section 11 of the Rights Agreement is
amended to add the following sentence after the first sentence of said Section:

                  "Notwithstanding anything in this Rights Agreement to the
                  contrary, neither (i) the execution of the Merger Agreement;
                  (ii) the acquisition of Common Shares pursuant to the Merger
                  Agreement or the consummation of the Merger; nor (iii) the
                  consummation of the other transactions contemplated in the
                  Merger Agreement, shall be deemed to be a Section 11(a)(i) or
                  (ii) Event or to cause the Rights to be adjusted or to become
                  exercisable in accordance with this Section 11."

         5.       AMENDMENT OF SECTION 13. Section 13 of the Rights Agreement is
amended to add the following sentence at the end thereof:

                  "Notwithstanding anything in this Rights Agreement to the
                  contrary, neither (i) the execution of the Merger Agreement;
                  (ii) the acquisition of Common Shares pursuant to the Merger
                  Agreement or the consummation of the Merger; nor (iii) the
                  consummation of the other transactions contemplated in the
                  Merger Agreement, shall be deemed to be a Section 13 Event or
                  to cause the Rights to be adjusted or to become exercisable in
                  accordance with Section 13."

         6.       AMENDMENT OF SECTION 27. Section 27 of the Rights Agreement is
amended to delete the notice address of the Rights Agent and to insert the
following in lieu thereof:

                  "BankBoston, N.A.
                  c/o Equiserve Limited Partnership
                  150 Royall Street
                  Canton, MA 02021
                  Attention: Client Administration"





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         7.       EFFECTIVENESS. This Amendment shall be deemed effective as of
the date first written above, as if executed on such date. Except as amended
hereby, the Rights Agreement shall remain in full force and effect and shall be
otherwise unaffected hereby.

         8.       MISCELLANEOUS. This Amendment shall be deemed to be a contract
made under the laws of The Commonwealth of Massachusetts and for all purposes
shall be governed by and construed in accordance with the laws of such state
applicable to contracts to be made and performed entirely within such state.
This Amendment may be executed in any number of counterparts, each of such
counterparts shall for all purposes be deemed to be an original, and all such
counterparts shall together constitute but one and the same instrument. If any
provisions, covenant or restriction of this Amendment is held by a court of
competent jurisdiction or other authority to be invalid, illegal or
unenforceable, the remainder of the terms, provisions, covenants and
restrictions of this Amendment shall remain in full force and effect and shall
in no way be effected, impaired or invalidated.

         EXECUTED under seal as of the date set forth above.



Attest:                                      XIONICS DOCUMENT
                                             TECHNOLOGIES, INC.


/s/ Suzanne M. Foster                        /s/ Carolyn E. Ramm
--------------------------                   --------------------------------
Name: Suzanne M. Foster                      Name: Carolyn E. Ramm
Title: Attorney                              Title: VP & General Counsel


Attest:                                      BANKBOSTON, N.A.
                                                 as Rights Agent:


/s/ Mary Ellen Kudera                        /s/ Tyler H. Haynes
--------------------------                   --------------------------------
Name: Mary Ellen Kudera                      Name: Tyler H. Haynes
Title: Account Manager                       Title: Administration Manager

                                                       [SEAL]





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