INSIGNIA SOLUTIONS PLC 41300 Christy Street Fremont, CA 94538 Telephone: 510 ###-###-#### Facsimile: 510 ###-###-####

Exhibit 10.04

INSIGNIA SOLUTIONS PLC

June 30, 2005

Fusion Capital Fund II, LLC

Re: Securities Subscription Agreement Dated as of February 10, 2005

Gentlemen:

This letter is being delivered to confirm our understanding with respect to certain issues under that certain Securities Subscription Agreement, dated as of February 10, 2005 (the “Subscription Agreement”), by and between INSIGNIA SOLUTIONS PLC, a company incorporated under the laws of England and Wales (the “Company”) and FUSION CAPITAL FUND II, LLC (“Fusion”), pursuant to which the Company has agreed to issue to Fusion the Ordinary Shares, 20 pence nominal value per share, of the Company represented by American Depository Shares (“ADSs”) in an amount up to Twelve Million Dollars ($12,000,000) in accordance with the terms of the Subscription Agreement. All capitalized terms used in this letter that are not defined in this letter shall have the meanings set forth in the Subscription Agreement.

Fusion and the Company hereby agree that the Company shall have until August 15, 2005 to file the registration statement referenced in Section 4(a) and that the June 30, 2005 date referred to in Section 11 shall be deemed to be September 30, 2005. The provisions set forth in Section 11 of the Subscription Agreement are hereby incorporated by reference herein.