<PAGE>

                                                                    ------------
                                                                    Exhibit 10.4
                                                                    ------------

CITY NATIONAL BANK
                                PROMISSORY NOTE

<TABLE>
<CAPTION>
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  Principal         Loan Date        Maturity        Loan No       Call       Collateral       Account       Officer       Initials
$4,000,000.00      01-02-2001       01-31-2002        38058                                    648112          SST           /s/JS
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<S>                <C>              <C>              <C>           <C>        <C>              <C>           <C>           <C>
References in the shaded area are for Lender's use only and do not limit the applicability of this document to any particular loan
                                                             or item.
                         Any item above containing "***" has been omitted due to text length limitations.
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Borrower:  DAILY JOURNAL CORPORATION,        Lender:   City National Bank, NA
           A SOUTH CAROLINA CORPORATION                Downtown Los Angeles Commercial Banking Center
           SUSTAIN TECHNOLOGIES, INC.,                 #034000
           A VIRGINIA CORPORATION                      633 West Fifth Street, Tenth Floor
           915 EAST 1ST STREET                         Los Angeles, CA  90071
           LOS ANGELES, CA  90012

====================================================================================================================================

Principal Amount:  $4,000,000.00                        Initial Rate:  9.250%                  Date of Note:  January 2, 2001
</TABLE>


PROMISE TO PAY. DAILY JOURNAL CORPORATION, A SOUTH CAROLINA CORPORATION; and
SUSTAIN TECHNOLOGIES, INC., a VIRGINIA CORPORATION ("Borrower") jointly and
severally promise to pay to City National Bank, NA ("Lender"), or order, in
lawful money of the United States of America, the principal amount of Four
Million & 00/100 Dollars ($4,000,000.00) or so much as may be outstanding,
together with interest on the unpaid outstanding principal balance of each
advance. Interest shall be calculated form the date of each advance until
repayment of each advance.

PAYMENT. Borrower will pay this loan in one payment of all outstanding principal
plus all accrued unpaid interest on January 31, 2002. In addition, Borrower will
pay regular monthly payments of all accrued unpaid interest due as of each
payment date, beginning January 31, 2001, with all subsequent interest payments
to be due on the last day of each month after that. Unless otherwise agreed or
required by applicable law, payments will be applied first to accrued unpaid
interest, then to principal, and any remaining amount to any unpaid collection
costs. The annual interest rate for this Note is computed on a 365/360 basis;
that is, by applying the ratio of the annual interest rate over a year of 360
days, multiplied by the outstanding principal balance, multiplied by the actual
number of days the principal balance is outstanding. Borrower will pay Lender at
Lender's address shown above or at such other place as Lender may designate in
writing.

VARIABLE INTEREST RATE. The interest rate on this Note is subject to change from
time to time based on changes in an index which is the City National Bank Prime
Rate (the "Index"). Prime Rate shall mean the rate most recently announced by
Lender at its principal office in Beverly Hills, California, as its "Prime
Rate". Any change in the Prime Rate shall become effective on the same business
day on which the Prime Rate shall change, without prior notice to Borrower.
Lender will tell Borrower the current Index rate upon Borrower's request. The
interest rate change will not occur more often than each day. Borrower
understands that Lender may make loans based on other rates as well. The Index
currently is 9.500%. The interest rate to be applied to the unpaid principal
balance of this Note will be at a rate of 0.250 percentage points under the
Index, resulting in an initial rate of 9.250%. NOTICE: Under no circumstances
will the interest rate on this note be more than the maximum rate allowed by
applicable law.

PREPAYMENT; MINIMUM INTEREST CHARGE. In any event, even upon full prepayment of
this Note, Borrower understands that Lender is entitled to a minimum interest
charge of $100.00. Other than Borrower's obligation to pay any minimum interest
charge, Borrower may pay without penalty all or a portion of the amount owed
earlier than it is due. Early payments will not, unless agreed to by Lender in
writing, relieve Borrower of Borrower's obligation to continue to make payments
of accrued unpaid interest. Rather, early payments will reduce the principal
balance due. Borrower agrees not to send Lender payments marked "paid in full",
"without recourse", or similar language. If Borrower sends such a payment,
Lender may accept it without losing any of Lender's rights under this Note, and
Borrower will remain obligated to pay any further amount owed to Lender. All
written communications concerning disputed amounts, including any check or other
payment instrument that indicates that the payment constitutes "payment in full"
of the amount owed or that is tendered with other conditions or limitations or
as full satisfaction of a disputed amount must be mailed or delivered to: City
National Bank, NA; Downtown Los Angeles Commercial Banking Center #034000; 633
West Fifth Street, Tenth Floor; Los Angeles, CA 90071.

INTEREST AFTER DEFAULT. Upon Borrower's failure to pay all amounts declared due
pursuant to this section, including failure to pay upon final maturity, Lender,
at its option, may, if permitted under applicable law, increase the variable
interest rate on this Note 5.000 percentage points.

DEFAULT.  Each of the following shall constitute an event of default ("Event of
Default") under this Note:

     Payment Default.  Borrower fails to make any payment when due under this
     Note.

     Other Defaults.  Borrower fails to comply with or to perform any other
     term, obligation, covenant or condition contained in this Note or in any of
     the related documents or to comply with or to perform any term, obligation,
     covenant or condition contained in any other agreement between Lender and
     Borrower.

     Default in Favor of Third Parties.  Borrower or any Grantor defaults under
     any loan, extension of credit, security agreement, purchase or sales
     agreement, or any other agreement, in favor of any other creditor or person
     that may materially affect any of Borrower's property or Borrower's ability
     to repay this Note or perform Borrower's obligations under this Note or any
     of the related documents.

     False Statements.  Any warranty, representation or statement made or
     furnished to Lender by Borrower or on Borrower's behalf under this Note or
     the related documents is false or misleading in any material respect,
     either now or at the time made or furnished or becomes false or misleading
     at any time thereafter.

     Insolvency.  The dissolution or termination of Borrower's existence as a
     going business, the insolvency of Borrower, the appointment of a receiver
     for any part of Borrower's property, any assignment for the benefit of
     creditors, any type of creditor workout, or the commencement of any
     proceeding under any bankruptcy or insolvency laws by or against Borrower.

     Creditor or Forfeiture Proceedings.  Commencement of foreclosure or
     forfeiture proceedings, whether by judicial proceeding, self-help,
     repossession or any other method, by any creditor of Borrower or by any
     governmental agency against any collateral securing the loan.  This
     includes a garnishment of any of Borrower's accounts, including deposit
     accounts, with Lender.  However, this Even of Default shall not apply if
     there is a good faith dispute by Borrower as to the validity or
     reasonableness of the claim which is the basis of the creditor or
     forfeiture proceeding and if Borrower gives Lender written notice of the
     creditor or forfeiture proceeding and deposits with Lender monies or a
     surety bond for the creditor or forfeiture proceeding, in an amount
     determined by Lender, in its sole discretion, as being an adequate reserve
     or bond for the dispute.
<PAGE>

                                PROMISSORY NOTE
                                  (Continued)
                                                                          Page 2
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     Events Affecting Guarantor.  Any of the preceding events occurs with
     respect to any guarantor, endorser, surety, or accommodation party of any
     of the indebtedness or any guarantor, endorser, surety, or accommodation
     party dies or becomes incompetent, or revokes or disputes the validity of,
     or liability under, any guaranty of the indebtedness.

     Change in Ownership.  Any change in ownership* of twenty-five percent (25%)
     or more of the common stock of Borrower.

     Adverse Change.  A material adverse change occurs in Borrower's financial
     condition, or Lender believes the prospect of payment or performance of
     this Note is impaired.  *as a result of a single transaction or a series of
     related transactions


LANDER'S RIGHTS.  Upon default, Lender may declare the entire unpaid principal
balance on this Note and all accrued unpaid interest immediately due, and then
Borrower will pay that amount.

ATTORNEYS' FEES; EXPENSES.  Lender may hire or pay someone else to help collect
the loan if Borrower does not pay.  Borrower will pay Lender that amount.  This
includes, subject to any limits under applicable law, Lender's attorneys' fees
and Lender's legal expenses, whether or not there is a lawsuit, including
attorneys' fees, expenses for bankruptcy proceedings (including efforts to
modify or vacate any automatic stay or injunction), and appeals.  Borrower also
will pay any court costs, in addition to all other sums provided by law.

GOVERNING LAW.  This Note will be governed by, construed and enforced in
accordance with federal law and the laws of the State of California.  This Note
has been accepted by Lender in the State of California.

CHOICE OF VENUE.  If there is a lawsuit, Borrower agrees upon Lender's request
to submit to the jurisdiction of the courts of LOS ANGELES County, State of
California.

RIGHT OF SETOFF. To the extent permitted by applicable law, Lender reserves a
right of setoff in all Borrower's accounts with Lender (whether checking,
savings, or some other account). This includes all accounts Borrower holds
jointly with someone else and all accounts Borrower may open in the future.
However, this does not include any IRA or Keogh accounts, or any trust accounts
for which setoff would be prohibited by law. Borrower authorizes Lender, to the
extent permitted by applicable law, to charge or setoff all sums owing on the
indebtedness against any and all such accounts.

LINE OF CREDIT.  This Note evidences a revolving line of credit.  Advances under
this Note may be requested either orally or in writing by Borrower or as
provided in this paragraph.  Lender may, but need not, require that all oral
requests be confirmed in writing.  All communications, instructions, or
directions by telephone or otherwise to Lender are to be directed to Lender's
office shown above.  The following person currently is authorized to request
advances and authorize payments under the line of credit until Lender receives
from Borrower, at Lender's address shown above, written notice of revocation of
his or her authority:  GERALD L. SALZMAN.  Borrower agrees to be liable for all
sums either:  (A) advanced in accordance with the instructions of an authorized
person or (B) credited to any of Borrower's accounts with Lender.  The unpaid
principal balance owing on this Note at any time may be evidenced by
endorsements on this Note or by Lender's internal records, including daily
computer print-outs.  Lender will have no obligation to advance funds under this
Note if:  (A) Borrower or any guarantor is in default under the terms of this
Note or any agreement that Borrower or any guarantor has with Lender, including
any agreement made in connection with the signing of this Note; (B) Borrower or
any guarantor ceases doing business or is insolvent; (C) any guarantor seeks,
claims or otherwise attempts to limit, modify or revoke such guarantor's
guarantee of this Note or any other loan with Lender; (D) Borrower has applied
funds provided pursuant to this Note for purposes other than those authorized by
Lender; or (E) Lender in good faith believes itself insecure.

SUCCESSOR INTERESTS.  The terms of this Note shall be binding upon Borrower, and
upon Borrower's heirs, personal representatives, successors and assigns, and
shall inure to the benefit of Lender and Lender's successors and assigns.

GENERAL PROVISIONS.  Lender may delay or forgo enforcing any of its rights or
remedies under this Note without losing them.  Each Borrower understands and
agrees that, with or without notice to Borrower, Lender may with respect to any
other Borrower (a) make one or more additional secured or unsecured loans or
otherwise extend additional credit; (b) alter, compromise, renew, extend,
accelerate, or otherwise change one or more times the time for payment or other
terms any indebtedness, including increases and decreases of the rate of
interest on the indebtedness; (c) exchange, enforce, waive, subordinate, fail or
decide not to perfect, and release any security, with or without the
substitution of new collateral; (d) apply such security and direct the order or
manner of sale thereof, including without limitation, any non-judicial sale
permitted by the terms of the controlling security agreements, as Lender in its
discretion may determine; (e) release, substitute, agree not to sue, or deal
with any one or more of Borrower' sureties, endorsers, or other guarantors on
any terms or in any manner Lender may choose; and (f) determine how, when and
what application of payments and credits shall be made on any other indebtedness
owing by such other Borrower.  Borrower and any other person who signs,
guarantees or endorses this Note, to the extent allowed by law, waive any
applicable statute of limitations, presentment, demand for payment, and notice
of dishonor.  Upon any change in the terms of this Note, and unless otherwise
expressly stated in writing, no party who signs this Note, whether as maker,
guarantor, accommodation maker or endorser, shall be released from liability.
All such parties agree that Lender may renew or extend (repeatedly and for any
length of time) this loan or release any party or guarantor or collateral; or
impair, fail to realize upon or perfect Lender's security interest in the
collateral; and take any other action deemed necessary by lender without the
consent of or notice to anyone.  All such parties also agree that Lender may
modify this loan without the consent of or notice to anyone other than the party
with whom the modification is made.  The obligations under this Note are joint
and several.
<PAGE>

                                PROMISSORY NOTE
                                  (Continued)
                                                                          Page 3
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PRIOR TO SIGNING THIS NOTE, EACH BORROWER READ AND UNDERSTOOD ALL THE PROVISIONS
OF THIS NOTE, INCLUDING THE VARIABLE INTEREST RATE PROVISIONS. EACH BORROWER
AGREES TO THE TERMS OF THE NOTE.

BORROWER ACKNOWLEDGES RECEIPT OF A COMPLETED COPY OF THIS PROMISSORY NOTE.


BORROWER:

DAILY JOURNAL CORPORATION, A SOUTH CAROLINA CORPORATION

By: /s/ Gerald L. Salzman
    ------------------------------------------------
    GERALD L. SALZMAN, President/CFO/Treasurer of
    DAILY JOURNAL CORPORATION, A SOUTH
    CAROLINA CORPORATION

SUSTAIN TECHNOLOGIES, INC., A VIRGINA CORPORATION


By: /s/ Gerald L. Salzman
    ------------------------------------------------
    GERALD L. SALZMAN, Secretary of SUSTAIN
    TECHNOLOGIES, INC., A VIRGINIA CORPORATION