<PAGE>   1
                                                                   EXHIBIT 10.77


                                SECOND AMENDMENT

        AMENDMENT, dated as of March 6, 1998 (this "Amendment"), to the Excess
Yield and Servicing Rights Purchase and Assumption Agreement, dated as of
January 22, 1998 (as amended, supplemented or otherwise modified from time to
time, the "Excess Yield Agreement"), among GREENWICH CAPITAL MARKETS, INC., as
purchaser (the "Purchaser"), and MEGO MORTGAGE CORPORATION, as seller (the
"Seller")

                                    RECITALS

        WHEREAS, pursuant to the Excess Yield Agreement, the Seller has sold and
transferred and the Purchaser has purchased the Excess Yield and Servicing
Rights with respect to Existing Conventional Loans (as defined in the Excess
Yield Agreement),

        WHEREAS, pursuant to the Excess Yield Agreement, the Seller contemplated
selling to the Purchaser the Existing FHA Loans on the FHA Loan Closing Date,
but the FHA Loan Closing Date has never taken place and such sale has never been
consummated;

        WHEREAS, the Seller desires to sell and transfer and the Purchaser
desires to purchase certain Second Pool Additional Conventional Loans (as
defined herein) pursuant to the Amended and Restated Master Loan Purchase and
Servicing Agreement, dated as of October 1, 1996 (the "Original Agreement");

        WHEREAS, the Seller desires to sell and transfer and the Purchaser
desires to purchase the Excess Yield and Servicing Rights with respect to the
Second Pool Additional Conventional Loans pursuant to the Excess Yield
Agreement, as modified by this Amendment; and

        WHEREAS, the Seller and the Purchaser desire to amend the Excess Yield
Agreement solely with respect to the Second Pool Additional Conventional Loans
referenced herein, and that with respect to Existing Loans (as defined in the
Excess Yield Agreement), the original Excess Yield Agreement terms shall
continue to govern, and with respect to the Additional Conventional Loans (as
defined in the Amendment, dated as of February 10, 1998, between Purchaser and
Seller (the "First Amendment")) the First Amendment shall continue to govern.

        NOW, THEREFORE, in consideration of the mutual agreements hereinafter
set forth and for other good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the Seller and the Purchaser hereby
agree as follows:

        1. Defined Terms. Unless otherwise defined herein, terms defined in the
Excess Yield Agreement are used herein as therein defined.


<PAGE>   2

        2. Amendments. Except as expressly amended hereby, the Excess Yield
Agreement shall remain in full force and effect in accordance with its terms,
without any waiver, amendment or modification of any provision thereof. All
provisions contained in this Amendment shall only apply to Second Pool
Additional Conventional Loans referenced herein and shall in no way modify the
terms relating to Existing Loans (as defined in the Excess Yield Agreement) or
the Additional Conventional Loans (as defined in the First Amendment) or
relating to. Additionally, sections of the Excess Yield Agreement not modified
by this Amendment shall, as of the Second Pool Additional Conventional Loan
Closing Date, apply to the Second Pool Additional Conventional Loans to the same
extent as they applied to the Existing Conventional Loans. Sections or
definitions of the Excess Yield Agreement corresponding to the section or
definition below are hereby amended by deleting such section or definition and
substituting in lieu thereof the following:

               a) Existing Conventional Loans. As defined in the Excess Yield
                  Agreement, and hereafter including all Second Pool Additional
                  Conventional Loans.

               b) Existing Loans: As defined in the Excess Yield Agreement, and
                  hereafter including all Second Pool Additional Conventional
                  Loans.

               c) Second Pool Additional Conventional Loans. All Second Pool
                  Additional Conventional Loans, as further described on the
                  Second Pool Additional Conventional Loan Schedule attached
                  hereto as Exhibit I.

               d) Second Pool Additional Conventional Loan Closing Date. The
                  date on which the Purchaser shall pay the Second Pool
                  Additional Conventional Loan Purchase Price to the Seller,
                  which date shall be March 6, 1998, or such other date or dates
                  as shall be mutually agreed upon by the parties hereto.

               e) Second Pool Additional Conventional Loan Purchase Price. The
                  price to be paid by the Purchaser to the Seller in exchange
                  for the Excess Yield and the Servicing Rights with respect to
                  the Second Pool Additional Conventional Loans as set forth in
                  Article III of the Excess Yield Agreement.

               f) Second Pool Additional Conventional Loan Cut-Off Date. The
                  close of business on March __, 1998.

               g) Servicing Expiration Date. The Servicing Expiration Date shall
                  mean March __, 1998, as such date may be extended from time to
                  time pursuant to Section 7.03 of the Excess Yield Agreement.

               h) Section 2.01. Second Pool Additional Conventional Loans.

                  (a) On the Second Pool Additional Conventional Loan Closing
                  Date, the Seller does hereby sell, transfer, assign, set over
                  and convey to the Purchaser (to the extent that the following
                  have not already been conveyed to the Purchaser under the
                  Original Agreement), without recourse, subject to 
   

                                       -2-
<PAGE>   3

                  the following sentence, but subject to the terms of this
                  Agreement, (i) all right, title and interest of the Seller in
                  and to the Excess Yield and the Servicing Rights with respect
                  to the Second Pool Additional Conventional Loans as of the
                  Second Pool Additional Conventional Loan Cut-Off Date, and
                  (ii) all of the Seller's rights under the PEC Sub-Servicing
                  Agreement with respect to Second Pool Additional Conventional
                  Loans as of the Second Pool Additional Conventional Loan
                  Cut-Off Date. Notwithstanding the foregoing sentence, the
                  Seller shall upon demand of the Purchaser repurchase from the
                  Purchaser, at the Repurchase Price, any such Second Pool
                  Additional Conventional Loan that thereafter becomes a
                  Delinquent Loan (as defined in the Original Agreement);
                  provided, however, that the Seller's liability pursuant to
                  this sentence shall not, in the aggregate, exceed the product
                  of (i) 0.025 and (ii) the aggregate "Cut-Off Date Principal
                  Balance" of the Second Pool Additional Conventional Loans as
                  set forth on Exhibit A (such product, the "Recourse Limit").

                  (b) On the Second Pool Additional Conventional Loan Closing
                  Date, the Purchaser does hereby (to the extent that the
                  following have not already been conveyed to the Purchaser
                  under the Original Agreement), (i) accept assignment of all
                  right, title and interest of the Seller in and to the Excess
                  Yield and the Servicing Rights with respect to the Second Pool
                  Additional Conventional Loans as of the Second Pool Additional
                  Conventional Loan Cut-Off Date and (ii) assume, subject to the
                  terms of this Agreement, all obligations of the Seller with
                  respect to the Servicing Rights and the PEC Sub-Servicing
                  Agreement relating to the Second Pool Additional Conventional
                  Loans as of the Second Pool Additional Conventional Loan
                  Cut-Off Date; provided, however, that the Purchaser expressly
                  does not assume any liability relating to or in any way
                  arising out of the foregoing obligations prior to the Second
                  Pool Additional Conventional Loan Cut-Off Date.

                  (c) Notwithstanding the foregoing and notwithstanding the
                  servicing provisions contained in the Original Agreement, for
                  the period beginning on the Second Pool Additional
                  Conventional Loan Closing Date and ending on the Servicing
                  Termination Date, the Seller shall service the Second Pool
                  Additional Conventional Loans pursuant to the revised
                  Servicing Addendum, attached hereto as Exhibit F, as described
                  in Article VII hereof.

                  (d) From and after the Second Pool Additional Conventional
                  Loan Closing Date, and notwithstanding the fact that certain
                  documents, files, records or other information which comprise
                  a portion of the Servicing Rights may remain at the Seller's
                  premises until the Servicing Termination Date or thereafter,
                  (i) the Seller's right to service the Second Pool Additional
                  Conventional Loans shall absolutely and irrevocably terminate
                  (subject to Article VII hereof) and (ii) the Seller shall have
                  no property, contract, 

                                       -3-
<PAGE>   4

                  possessory or other right, title or interest of any nature
                  whatsoever in or to the Servicing Rights (including any such
                  documents, files, records or other information at the Seller's
                  premises, all of which shall be the sole property of the
                  Purchaser) or the Excess Yield with respect to the Second Pool
                  Additional Conventional Loans. The Purchaser and Seller agree
                  that no termination fee, liquidated damages or any other fee
                  or monies triggered by the termination of the Seller's right
                  to service the Second Pool Additional Conventional Loans shall
                  be payable to the Servicer as a result of the termination of
                  such servicing and the transactions contemplated by this
                  Agreement, it being expressly understood that the payment of
                  the Second Pool Additional Conventional Loan Purchase Price by
                  the Purchaser shall constitute, in and of itself, the full
                  consideration payable to the Seller for its sale of the Excess
                  Yield and the Servicing Rights with respect to the Second Pool
                  Additional Conventional Loans and the other transactions
                  contemplated hereby; provided, however, that the Seller shall
                  be entitled to receive the Servicing Fee as and when
                  contemplated by the Original Agreement, as modified by Exhibit
                  F, with respect to its servicing of the Second Pool Additional
                  Conventional Loans for the Purchaser for the period from the
                  Second Pool Additional Conventional Loan Cut-Off Date until
                  the Servicing Termination Date.

               i) Section 2.03 Intention of the Parties.

                          It is the express intention of the parties hereto that
                  the transactions contemplated by this Agreement and the
                  Original Agreement be, and be construed as, a sale of rights
                  and interests relating to the Second Pool Additional
                  Conventional Loans by the Seller and not a pledge of the
                  rights and interests relating to the Second Pool Additional
                  Conventional Loans by the Seller to the Purchaser to secure a
                  debt or other obligation of the Seller. However, in the event
                  that the Second Pool Additional Conventional Loans and other
                  rights transferred under this Agreement are held to be
                  property of the Seller, or if for any reason this Agreement is
                  held or deemed to create a security interest in the Second
                  Pool Additional Conventional Loans and related rights then it
                  is intended that (a) this Agreement shall also be deemed to be
                  a security agreement within the meaning of the Uniform
                  Commercial Code of any applicable jurisdiction and the Seller
                  hereby grants to the Purchaser a security interest in all of
                  Seller's right, title and interest, whether now owned or
                  hereafter acquired, in and to the Second Pool Additional
                  Conventional Loans; (b) the possession by the Purchaser of the
                  related Notes or such other items of property as constitute
                  instruments, money, negotiable documents or chattel paper
                  shall be deemed to be "possession by the secured party", or
                  possession by a purchaser or a person designated by such
                  secured party, for purposes of perfecting the security
                  interest pursuant to the Uniform Commercial Code of any
                  applicable jurisdiction (including, without limitations,
                  Section 9-305, 8-313 or 8-321 

                                      -4-
<PAGE>   5

                  thereof); (c) notifications to persons holding such property,
                  and acknowledgments, receipts or confirmations from persons
                  holding such property, shall be deemed notifications to, or
                  acknowledgments, receipts or confirmations from, financial
                  intermediaries, bailees or agents (as applicable) of the
                  Purchaser for the purpose of perfecting such security interest
                  under applicable law; and (d) for purposes of this Agreement
                  and the Pricing Letter, "Loan Documents' shall include UCC-1
                  financing statements in form acceptable for filing in the
                  applicable jurisdictions in which are located the principal
                  place of business and the executive offices of the Seller and
                  executed by the Seller in favor of the Purchaser.

               j)   ARTICLE IV PURCHASER DISPOSITION

                          The Purchaser and the Seller understand that the
                  Purchaser shall have the right to sell the Second Pool
                  Additional Conventional Loans in whole or in part in its
                  discretion on a servicing released or servicing retained
                  basis. The Seller shall not be entitled to receive any
                  additional payments in connection with such a disposition.

               k) Section 9.01. Second Pool Additional Conventional Loan
                  Closing.

                  (a) The closing for the purchase and sale of the Excess Yield
                      and the Servicing Rights with respect to the Second Pool
                      Additional Conventional Loans, shall take place on the
                      Second Pool Additional Conventional Loan Closing Date. At
                      the Purchaser's option, the closing shall be either: by
                      telephone, confirmed by letter or wire as the parties
                      shall agree; or conducted in person, at such place as the
                      parties shall agree.

                  (b) The closing shall be subject to the following conditions:

                      (i)   all of the representations and warranties of the
                          Seller and the Purchaser under this Agreement shall be
                          true and correct as of the Second Pool Additional
                          Conventional Loan Closing Date and no event shall have
                          occurred which, with notice or the passage of time,
                          would constitute a default under this Agreement;

                      (ii)  the Purchaser shall have received, or the
                          Purchaser's attorneys shall have received in escrow,
                          all Closing Documents as specified in Section 9.01(c)
                          of this Agreement, in such forms as are agreed upon
                          and acceptable to the Seller and the Purchaser, duly
                          executed by all signatories other than the Purchaser
                          as required pursuant to the respective terms thereof;

                      (iii)  the Seller shall have received the amount of the
                          Second Pool Additional Conventional Loan Purchase
                          Price by wire transfer of 

                                      -5-
<PAGE>   6

                          immediately available federal funds to the account
                          designated by the Seller;

                      (iv)  PEC shall have consented to the assignment of the 
                          PEC Sub-Servicing Agreement with respect to the Second
                          Pool Additional Conventional Loans on such terms and
                          conditions as shall be acceptable to the Purchaser in
                          its sole discretion, including without limitation
                          terms and conditions relating to the Purchaser's
                          ability to terminate PEC as subservicer of the PEC
                          Sub-Servicing Agreement with respect to the Second
                          Pool Additional Conventional Loans as contemplated
                          hereunder;

                      (v)   the "Collection Account" and the "REO Account"
                          referenced in the Original Agreement shall be in the
                          name of the Purchaser within three (3) Business Days
                          following the Second Pool Additional Conventional Loan
                          Closing Date; and

                      (vi)  all other terms and conditions of this Agreement to
                          be performed or satisfied on or before the Second Pool
                          Additional Conventional Loan Closing Date shall have
                          been complied with.

                  (c) The closing documents to be delivered on the Second Pool
                      Additional Conventional Loan Closing Date shall consist of
                      fully executed originals of the following documents:

                      (i)   this Agreement;

                      (ii)  an Officer's Certificate from the Seller in the form
                            attached hereto as Exhibit B;

                      (iii) an Opinion of Counsel from the Seller in the form 
                            attached hereto as Exhibit C;

                      (iv)  a "true sale" Opinion of Counsel from the Seller, in
                            form and substance satisfactory to the Purchaser;

        3. Effectiveness. This Amendment shall become effective upon receipt by
the Purchaser of evidence satisfactory to the Purchaser that this Amendment has
been executed and delivered by the Seller.

        4. Counterparts. This Amendment may be executed by one or more of the
parties hereto on any number of separate counterparts and all of said
counterparts taken together shall be deemed to constitute one and the same
instrument.

        5. Expenses. The Seller agrees to pay and reimburse the Purchaser for
all of the out-of-pocket costs and expenses incurred by the Purchaser in
connection with the preparation, 

                                      -6-

<PAGE>   7

execution and delivery of this Amendment, including, without limitation, the
fees and disbursements of counsel to the Purchaser.

        6. Applicable Law. THIS AMENDMENT SHALL BE GOVERNED BY, AND CONSTRUED
AND INTERPRETED IN ACCORDANCE WITH, THE LAW OF THE STATE OF NEW YORK.

                            [SIGNATURE PAGES FOLLOW]





                                      -7-


<PAGE>   8




        IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered as of the day and year first above written.



                                            MEGO MORTGAGE CORPORATION
                                                   as Seller



                                            By:
                                               ---------------------------------
                                               Name:
                                               Title:



                                            GREENWICH CAPITAL MARKETS, INC.,
                                             as Purchaser



                                            By:
                                               ---------------------------------
                                               Name:
                                               Title:



                                      -8-





<PAGE>   9






                                    EXHIBIT I

                SECOND POOL ADDITIONAL CONVENTIONAL LOAN SCHEDULE