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                                                                     Exhibit 4.1

                              [FRISBY LETTERHEAD]

MUSI Investments, S.A.
231 Val des Bons Malades
L-2121 Luxembourg-Kirchberg

         Re:      Loan Agreement dated May 14, 2001 by and between MUSI
                  Investments, S.A. and Frisby Technologies, Inc. (the "Loan
                  Agreement"); capitalized terms used in this letter agreement
                  shall have the meanings provided in the Loan Agreement.

Gentlemen:

                  This letter is to confirm our mutual understanding and
agreement that MUSI Investments, S.A. ("MUSI") consents to the following actions
by Frisby Technologies, Inc. ("Borrower"): (1) Frisby Technologies shall be
required to apply the net cash proceeds of Private Placements closed after May
14, 2001 to repay the outstanding principal amount of the MUSI Loan only to the
extent that the aggregate net cash proceeds of such Private Placements, plus the
net cash proceeds of the Designated Private Placements exceed $2,550,000; (2)
Interest on the MUSI Loan shall be payable quarterly in arrears provided that
the interest payment due on October 1, 2001 and subsequent payments of interest
will be deferred until the maturity date of the Convertible Note; and (3) Frisby
shall be permitted to incur short-term unsecured indebtedness up to an aggregate
amount outstanding of $250,000 at any one time which amount may be owing to
Persons other than MUSI.

                  MUSI hereby consents to the foregoing matters and waives any
default or event of default arising under the Loan Agreement or any other Loan
Document as a result of the foregoing matters. In furtherance and not in
limitation of the foregoing, MUSI and the Borrower agree as follows:

                  1. Sections 2C and 2D of the Loan Agreement are amended and
restated to read in their entirety as follows:

                  C. Borrower shall apply the aggregate net cash proceeds of all
         Private Placements, including the Designated Private Placements,
         received by Borrower in excess of Two Million Five Hundred Fifty
         Thousand Dollars ($2,550,000) to repay any outstanding principal amount
         of the MUSI Loan until the same has been repaid in full.

                  D. Interest and Principal. Interest on the principal amount
         outstanding under the MUSI Loan from time to time shall accrue at a
         variable rate of the Prime Rate, plus seventy-five basis points (.75%)
         per annum, which accrued interest shall be payable quarterly in arrears
         except that, beginning with the payment due on October 1, 2001, said



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payment and future interest payments will be deferred until the Maturity Date.
The principal of the Convertible Note shall be repaid in full on the Maturity
Date, together with all accrued but unpaid interest.

                  2. Section 7E(5) of the Loan Agreement is amended and restated
to read as follows:

                  "(5) short-term unsecured indebtedness up to an aggregate
         amount outstanding of $250,000 at any one time."

                  3. The second sentence in the second paragraph of Section 4 of
the Convertible Note is amended and restated to read as follows:

          "Interest thereon shall be paid: (1) for the quarter ending June 30,
          2001, on the first business day after the end of such quarter; and (2)
          for the quarters ending September 30, 2001 and December 31, 2001, on
          January 2, 2002."

                  Except for the amendments set forth above, the text of the
Loan Agreement and the Convertible Note shall remain unchanged and in full force
and effect; provided, however, that if there is any conflict between the terms
of the Loan Agreement, the Convertible Note or any other Loan Document with the
amendments set forth above, the amendments set forth above shall control. Please
confirm your agreement to the foregoing by executing this letter below and
returning it to me at your earliest convenience.

                                           Very truly yours,

                                           FRISBY TECHNOLOGIES, INC.

                                           By: /s/  John L. Ruggiero
                                              ----------------------------
                                           Name:  John L. Ruggiero
                                           Title:  Chief Financial Officer
Agreed:
Date: September 13, 2001

MUSI INVESTMENTS, S.A.

By:  /s/ Luca Bassani Antivari
   ---------------------------
Name:  Luca Bassani Antivari
Title:  Managing Director

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                  Gregory S. Frisby consents to the foregoing modifications and
agrees that the Continuing and Unconditional Guaranty dated May 14, 2001
executed by Gregory S. Frisby for the benefit of MUSI Investments, S.A.
respecting the indebtedness of Frisby Technologies, Inc. remains in full force
and effect.


                                               /s/ Gregory S. Frisby
                                               -----------------------
                                               Gregory S. Frisby


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