AMENDMENT TO THE SYNACOR, INC. (F/K/A CHEK, INC.) 2000 STOCK PLAN

Exhibit 10.2.5

AMENDMENT TO THE

SYNACOR, INC. (F/K/A CHEK, INC.)

2000 STOCK PLAN

The 2000 Stock Plan (the “Plan”) was adopted on December 5, 2000. Unless otherwise defined herein, all capitalized terms shall have the meaning set forth in the Plan.

Section 3 of the Plan shall be amended in its entirety to read as follows:

“3. Stock Subject to the Plan. Subject to the provisions of Section 14 of the Plan, the maximum aggregate number of Shares that may be sold under the Plan is 6,979,554 Shares of Common Stock. The Shares may be authorized, but unissued, or reacquired Common Stock. If an award should expire or become unexercisable for any reason without having been exercised in full, or is surrendered pursuant to an Option Exchange Program, the unpurchased Shares that were subject thereto shall, unless the Plan shall have been terminated, become available for future grant under the Plan. In addition, any Shares of Common Stock which are retained by the Company upon exercise of an award in order to satisfy the exercise or purchase price for such award or any withholding taxes due with respect to such exercise or purchase shall be treated as not issued and shall continue to be available under the Plan. Shares issued under the Plan and later repurchased by the Company pursuant to any repurchase right which the Company may have shall not be available for future grant under the Plan.”

Except as expressly amended hereby, the Plan shall remain unchanged and in full force and effect and is hereby ratified and confirmed.