<PAGE>   1
                                                                   EXHIBIT 10.25

                                AMENDMENT #A01 TO

                               PURCHASE AGREEMENT

                                     BETWEEN

                               EXABYTE CORPORATION

                                       AND

                             SINGAPORE SHINEI SANGYO

With reference to the Purchase Agreement effective March 28, 1999,
("Agreement"), Exabyte Corporation ("Exabyte") and Singapore Shinei Sangyo
("Seller") expressly agree to the following amendment which shall be effective
as of the date last signed below.

Exabyte and Seller hereby amend the Agreement as follows:

1)   Reference Section 1.3, "Product" Definition.

     Product shall mean those items manufactured, assembled, or sold by the
Seller which are listed in Appendix 1 of this Agreement (and those items, if any
hereafter added by the parties to Appendix I), including the Product defined by
the specifications included in Exhibit A.

2)   Reference Section 1 DEFINITIONS.

     The Parties agree to add the following definition as Section 1.8 to the
     Agreement:

     1.8 "Spare Parts" means all parts or components of Product which are listed
     in Appendix V of this Agreement as amended from time to time by written
     agreement of the Parties.

3)   Reference: Section 5, PRODUCT SUPPLY.

     The Parties agree to incorporate as Section 5.4.4 - Supply of Spare Parts

Seller shall offer for sale Spare Parts necessary for the maintenance of Product
during the term of this Agreement and for a period of five (5) years after the
date of the last Product shipment by Exabyte as may be mutually agreed to by the
parties on a case by case basis. Only those Spare Parts considered to
sub-assemblies or value-add are subject to the above five (5) year requirement.
Spare Parts shall be interchangeable with and of the same quality as those
installed in Product and will be produced or inspected by Seller, in the same
manner and according to the same procedure as Seller uses for parts installed in
Product.

<PAGE>   2

4)   Reference: Section 6.3 Effects of Termination.

The Parties agree to incorporate the following Sections to the Agreement 6.3.1 -
Transition Period: - 6.3.4 Right of Entry.

6.3.1 Transition Period

Upon termination or expiration of this Agreement, for any reason, a transition
period will commence lasting for a time period as may be mutually agreed to, but
in no case for less time than necessary to transfer Seller's obligations
undertaken by this Agreement to Exabyte or a third party elected by Exabyte and
in no case longer than one (1) year from the effective date of the termination.
Such transition period shall start on the effective day of the Notice as
provided for in Section 9.4.

Both parties will make commercially reasonable efforts to execute a mutually
acceptable transition plan for the transfer of the manufacture and supply of
Product (the "Plan") within thirty (30) days of the effective date of the Notice
of termination. Should the parties fail to execute such a Plan in the prescribed
time frame, Exabyte shall provide a reasonable Plan to Seller. Seller agrees to
make best effort to comply with the Plan submitted by Exabyte.

6.3.2 Transition Plan

The Plan shall detail a timetable to address how the transfer of the
manufacturing of Product shall take place and will establish the process whereby
funded tooling as listed in Appendix V, shall be transferred and including but
not limited to the following: suspending all assembly operation and production
required by purchase orders, delivering completed Products, returning any loaned
or leased equipment and work-in-progress reporting.

Exabyte shall be liable for payment for any unamortized portion of funded
tooling, which may exist upon completion of the transition period.

6.3.3 Supply of Product

Seller agrees to continue to manufacture and ship the Product during the
transition period and further agrees to fully comply with the terms and
conditions of the Agreement until the completion of the transfer of the
manufacturing of Product to Exabyte or as otherwise agreed.

6.3.4 Right of Entry

Exabyte may, at its option, and by giving Seller reasonable notice, enter any
facility maintained by Seller or its affiliates (including any Seller
subcontractor Facility) at which any materials and equipment listed in Appendix
V are located and retrieve such materials and equipment. Seller agrees to
cooperate with Exabyte and hereby grants to Exabyte the right of entry on its
property for this limited purpose. Any such removal of Exabyte property shall
not unreasonably interfere with Seller's activities.

<PAGE>   3

Nothing herein, except as specifically amended herein, is intended to and shall
not be construed to render ineffective or otherwise change any section,
provision or term of this Agreement.

EXABYTE CORPORATION                    SINGAPORE SHINEI SANGYO

By:                                    By:
   --------------------------------       --------------------------------------

Title:                                 Title:
      -----------------------------          -----------------------------------

Date:                                  Date:
     ------------------------------         ------------------------------------