WARRANT ASSIGNMENT, ASSUMPTION AND AMENDMENT AGREEMENT among FIRSTMARK HORIZON ACQUISITION CORP., STARRY GROUP HOLDINGS, INC. and CONTINENTAL STOCK TRANSFER & TRUST COMPANY Dated March 28, 2022

Exhibit 4.2

Execution Version

WARRANT ASSIGNMENT, ASSUMPTION AND AMENDMENT AGREEMENT

among

FIRSTMARK HORIZON ACQUISITION CORP.,

STARRY GROUP HOLDINGS, INC.

and

CONTINENTAL STOCK TRANSFER & TRUST COMPANY

Dated March 28, 2022

THIS WARRANT ASSIGNMENT, ASSUMPTION AND AMENDMENT AGREEMENT (this “Agreement”), dated March 28, 2022, is made by and among FirstMark Horizon Acquisition Corp., a Delaware corporation (the “SPAC”), Starry Group Holdings, Inc. (formerly Starry Holdings, Inc.), a Delaware corporation (“New Starry”), and Continental Stock Transfer & Trust Company, a New York corporation, as warrant agent (in such capacity, the “Warrant Agent”), and amends the Warrant Agreement (the “Existing Warrant Agreement”), dated October 5, 2020, by and between SPAC and the Warrant Agent. Capitalized terms used but not defined herein shall have the meaning ascribed to such terms in the Existing Warrant Agreement.

WHEREAS, pursuant to the Existing Warrant Agreement, the SPAC issued (a) 6,853,333 Private Placement Warrants to the Sponsor and (b) 13,800,000 Public Warrants;

WHEREAS, on October 6, 2021, the SPAC, New Starry, Starry, Inc., a Delaware corporation, and Sirius Merger Sub, Inc., a Delaware corporation, and a wholly owned subsidiary of the SPAC, entered into an agreement and plan of merger (as amended, modified or supplemented, from time to time, the “Merger Agreement”);

WHEREAS, all of the Warrants are governed by the Existing Warrant Agreement;

WHEREAS, pursuant to the Merger Agreement, the SPAC will merge with and into New Starry, with New Starry surviving such merger (the “SPAC Merger”), and as a result of the SPAC Merger, the holders of shares of Common Stock of the SPAC shall become holders of shares of New Starry’s Class A common stock, par value $0.0001 per share (“New Starry Class A Common Stock”);

WHEREAS, upon consummation of the SPAC Merger, as provided in Section 4.5 of the Existing Warrant Agreement and Section 3.01(a)(iii) of the Merger Agreement, the Warrants will no longer be exercisable for shares of Common Stock of the SPAC but instead will be exercisable (subject to the terms of the Existing Warrant Agreement, as amended by this Agreement) for shares of New Starry Class A Common Stock;

WHEREAS, the Board of Directors of the SPAC has determined that the consummation of the transactions contemplated by the Merger Agreement will constitute a Business Combination;

WHEREAS, in connection with the SPAC Merger, the SPAC desires to assign all of its right, title and interest in the Existing Warrant Agreement to New Starry, and New Starry wishes to accept such assignment; and

WHEREAS, Section 9.8 of the Existing Warrant Agreement provides that the SPAC and the Warrant Agent may amend the Existing Warrant Agreement without the consent of any Registered Holders as the parties may deem necessary or desirable and that the parties deem shall not adversely affect the interest of the Registered Holders under the Existing Warrant Agreement.

NOW, THEREFORE, in consideration of the mutual agreements herein contained, the parties hereto agree as follows:

Section 1. Assignment and Assumption; Consent.

1.1    Assignment and Assumption. As of and with effect on and from the SPAC Merger Effective Time (as defined in the Merger Agreement): the SPAC hereby assigns to New Starry all of the SPAC’s right, title and interest in and to the Existing Warrant Agreement (as amended hereby); New Starry hereby assumes, and agrees to pay, perform, satisfy and discharge in full, as the same become due, all of the SPAC’s liabilities and obligations under the Existing Warrant Agreement (as amended hereby) arising on, from and after the SPAC Merger Effective Time.

1.2    Consent. The Warrant Agent hereby consents to (i) the assignment of the Existing Warrant Agreement by the SPAC to New Starry pursuant to this Section 1 and the assumption of the Existing Warrant Agreement by New Starry from the SPAC pursuant to Section 1 hereof, in each case effective as of the SPAC Merger Effective Time, and (ii) the continuation of the Existing Warrant Agreement (as amended hereby), in full force and effect from and after the SPAC Merger Effective Time.

Section 2. Amendment of Existing Warrant Agreement.

2.1    Effective as of the SPAC Merger Effective Time, the SPAC and the Warrant Agent hereby amend the Existing Warrant Agreement as provided in this Section 2, and acknowledge and agree that the amendments to the Existing Warrant Agreement set forth in this Section 2 are to provide for the delivery of Alternative Issuance pursuant to Section 4.5 of the Existing Warrant Agreement (in connection with the SPAC Merger and the transactions contemplated by the Merger Agreement).

2.2    References to the “Company”. All references to the “Company” in the Existing Warrant Agreement (including all Exhibits thereto) shall be references to New Starry.

2.3    References to Common Stock. All references to “Common Stock” in the Existing Warrant Agreement (including all Exhibits thereto) shall be references to shares of New Starry Class A Common Stock.

2.4    References to Business Combination. All references to “Business Combination” in the Existing Warrant Agreement (including all Exhibits thereto) shall be references to the transactions contemplated by the Merger Agreement, and references to “the completion of its initial Business Combination,” “the completion of the Company’s initial Business Combination” and all variations thereof in the Existing Warrant Agreement (including all Exhibits thereto) shall be references to the Acquisition Merger Closing (as defined in the Merger Agreement).

2.5    Warrant Certificate. Exhibit A to the Existing Warrant Agreement is hereby amended by deleting Exhibit A in its entirety and replacing it with a new Exhibit A attached hereto.

2.6    Notice Clause. Section 9.2 of the Existing Warrant Agreement is hereby deleted and replaced with the following:

“Notices. Any notice, statement or demand authorized by this Agreement to be given or made by the Warrant Agent or by the holder of any Warrant to or on the Company shall be sufficiently given when so delivered if by hand or overnight delivery or if sent by certified mail or private courier service within five (5) days after deposit of such notice, postage prepaid, addressed (until another address is filed in writing by the Company with the Warrant Agent), as follows:

Starry Group Holdings, Inc.

c/o Starry, Inc.

▇▇ ▇▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇ ▇▇▇▇▇

▇▇▇▇▇▇, ▇▇ ▇▇▇▇▇

Attn: ▇▇▇▇ ▇▇▇▇▇▇▇▇▇, Chief Legal Officer

E-mail: ▇▇▇▇▇▇▇▇▇▇@▇▇▇▇▇▇.▇▇▇

with a copy (which shall not constitute notice) to:

▇▇▇▇▇▇ & ▇▇▇▇▇▇▇ LLP

▇▇▇▇ ▇▇▇▇▇▇ ▇▇ ▇▇▇ ▇▇▇▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

Attn: ▇▇▇▇▇▇ ▇▇▇▇▇▇

E-mail: ▇▇▇▇▇▇.▇▇▇▇▇▇@▇▇.▇▇▇

Attn: ▇▇▇▇ ▇▇▇▇▇▇▇

E-mail: ▇▇▇▇.▇▇▇▇▇▇▇@▇▇.▇▇▇

Any notice, statement or demand authorized by this Agreement to be given or made by the holder of any Warrant or by the Company to or on the Warrant Agent shall be sufficiently given when so delivered if by hand or overnight delivery or if sent by certified mail or private courier service within five (5) days after deposit of such notice, postage prepaid, addressed (until another address is filed in writing by the Warrant Agent with the Company), as follows:

Continental Stock Transfer & Trust Company

▇▇▇ ▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇ ▇▇▇▇▇

▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇

Attention: Compliance Department”

Section 3. Miscellaneous Provisions.

3.1    Effectiveness of the Amendment. Each of the parties hereto acknowledges and agrees that the effectiveness of this Agreement shall be expressly subject to the occurrence of the SPAC Merger and substantially contemporaneous occurrence of the SPAC Merger Closing (as defined in the Merger Agreement) and shall automatically be terminated and shall be null and void if the Merger Agreement shall be terminated for any reason.

3.2    Successors. All the covenants and provisions of this Agreement by or for the benefit of New Starry, the SPAC or the Warrant Agent shall bind and inure to the benefit of their respective successors and assigns.

3.3    Applicable Law and Exclusive Forum. The validity, interpretation, and performance of this Agreement shall be governed in all respects by the laws of the State of New York. Subject to applicable law, each of New Starry and the SPAC hereby agrees that any action, proceeding or claim against it arising out of or relating in any way to this Agreement shall be brought and enforced in the courts of the State of New York or the United States District Court for the Southern District of New York, and irrevocably submits to such jurisdiction, which jurisdiction shall be exclusive forum for any such action, proceeding or claim. Each of New Starry and the SPAC hereby waives any objection to such exclusive jurisdiction and that such courts represent an inconvenient forum. Notwithstanding the foregoing, the provisions of this paragraph will not apply to suits brought to enforce any liability or duty created by the Exchange Act or any other claim for which the federal district courts of the United States of America are the sole and exclusive forum.

3.4    Any person or entity purchasing or otherwise acquiring any interest in the Warrants shall be deemed to have notice of and to have consented to the forum provisions in this Section 3. If any action, the subject matter of which is within the scope the forum provisions above, is filed in a court other than a court located within the State of New York or the United States District Court for the Southern District of New York (a “foreign action”) in the name of any warrant holder, such warrant holder shall be deemed to have consented to: (x) the personal jurisdiction of the state and federal courts located within the State of New York or the United States District Court for the Southern District of New York in connection with any action brought in any such court to enforce the forum provisions (an “enforcement action”), and (y) having service of process made upon such warrant holder in any such enforcement action by service upon such warrant holder’s counsel in the foreign action as agent for such warrant holder.

3.5    Counterparts. This Agreement may be executed in any number of original or facsimile counterparts and each of such counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument. A signed copy of this Agreement delivered by facsimile, e-mail or other means of electronic transmission shall be deemed to have the same legal effect as delivery of an original signed copy of this Agreement.

3.6    Effect of Headings. The section headings herein are for convenience only and are not part of this Agreement and shall not affect the interpretation thereof.

3.7    Severability. This Agreement shall be deemed severable, and the invalidity or unenforceability of any term or provision hereof shall not affect the validity or enforceability of this Agreement or of any other term or provision hereof. Furthermore, in lieu of any such invalid or unenforceable term or provision, the parties hereto intend that there shall be added as a part of this Agreement a provision as similar in terms to such invalid or unenforceable provision as may be possible and be valid and enforceable.

(Signature Page Follows)

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed as of the date first above written.

[Signature Page to Warrant Assignment, Assumption and Amendment Agreement]

EXHIBIT A

FORM OF WARRANT CERTIFICATE

See attached.

[Form of Warrant Certificate]

[FACE]

Number ___

Warrants

THIS WARRANT SHALL BE NULL AND VOID IF NOT EXERCISED PRIOR TO

THE EXPIRATION OF THE EXERCISE PERIOD PROVIDED FOR

IN THE WARRANT AGREEMENT DESCRIBED BELOW

STARRY GROUP HOLDINGS, INC.

Incorporated Under the Laws of the State of Delaware

CUSIP 85572U 110

Warrant Certificate

This warrant certificate (this “Warrant Certificate”) certifies that                 , or registered assigns, is the registered holder of                  warrant(s) evidenced hereby (the “Warrants,” and each, a “Warrant”) to purchase shares of Class A common stock, $0.0001 par value per share (“Common Stock”), of Starry Group Holdings, Inc., a Delaware corporation (the “Company”). Each Warrant entitles the holder, upon exercise during the period set forth in the Warrant Agreement (as defined below), to receive from the Company that number of fully paid and non-assessable shares of Common Stock as set forth below, at the exercise price (the “Exercise Price”) as determined pursuant to the Warrant Agreement, payable in lawful money of the United States of America (or through “cashless exercise” as provided for in the Warrant Agreement) upon surrender of this Warrant Certificate and payment of the Exercise Price at the office or agency of the Warrant Agent referred to below, subject to the conditions set forth herein and in the Warrant Agreement. Defined terms used in this Warrant Certificate but not defined herein shall have the meanings given to them in the Warrant Agreement.

Each whole Warrant is initially exercisable for 1.2415 fully paid and non-assessable shares of Common Stock. Fractional shares of Common Stock shall not be issued upon exercise of any Warrant. If, upon the exercise of Warrants, a holder would be entitled to receive a fractional interest in a share of Common Stock, the Company shall, upon exercise, round down to the nearest whole number of shares of Common Stock to be issued to the warrantholder. The number of shares of Common Stock issuable upon exercise of the Warrants is subject to adjustment upon the occurrence of certain events as set forth in the Warrant Agreement.

The initial Exercise Price is equal to $11.50 per 1.2415 shares. The Exercise Price is subject to adjustment upon the occurrence of certain events as set forth in the Warrant Agreement.

Subject to the conditions set forth in the Warrant Agreement, the Warrants may be exercised only during the Exercise Period and, to the extent not exercised by the end of such Exercise Period, such Warrants shall become void. The Warrants may be redeemed, subject to certain conditions, as set forth in the Warrant Agreement.

Reference is hereby made to the further provisions of this Warrant Certificate set forth on the reverse hereof and such further provisions shall for all purposes have the same effect as though fully set forth at this place.

This Warrant Certificate shall not be valid unless countersigned by the Warrant Agent, as such term is used in the Warrant Agreement.

This Warrant Certificate shall be governed by and construed in accordance with the internal laws of the State of New York, without regard to conflicts of laws principles thereof.

[Signature Pages Follow]

[Form of Warrant Certificate]

[Reverse]

The Warrants evidenced by this Warrant Certificate are part of a duly authorized issue of Warrants entitling the holder on exercise to receive shares of Common Stock and are issued or to be issued pursuant to a warrant agreement, dated as of October 5, 2020, as duly executed and delivered by FirstMark Horizon Acquisition Corp. (“SPAC”) to Continental Stock Transfer & Trust Company, a New York corporation, as warrant agent (the “Warrant Agent”), as amended by the Warrant Assignment, Assumption and Amendment Agreement, dated as of March 28, 2022, by and among SPAC, the Warrant Agent and the Company (as amended, the “Warrant Agreement”), which Warrant Agreement is hereby incorporated by reference in and made a part of this instrument and is hereby referred to for a description of the rights, limitation of rights, obligations, duties, and immunities thereunder of the Warrant Agent, the Company, and the holders (the words “holders” or “holder” meaning the Registered Holders or Registered Holder, respectively) of the Warrants. A copy of the Warrant Agreement may be obtained by the holder hereof upon written request to the Company.

Warrants may be exercised at any time during the Exercise Period set forth in the Warrant Agreement. The holder of Warrants evidenced by this Warrant Certificate may exercise them by surrendering this Warrant Certificate, with the form of Election to Purchase set forth hereon properly completed and executed, together with payment of the Exercise Price as specified in the Warrant Agreement (or through “cashless exercise” as provided for in the Warrant Agreement) at the principal corporate trust office of the Warrant Agent. In the event that upon any exercise of Warrants evidenced hereby the number of Warrants exercised shall be less than the total number of Warrants evidenced hereby, there shall be issued to the holder hereof or his, her, or its assignee, a new Warrant Certificate evidencing the number of Warrants not exercised.

Notwithstanding anything else in this Warrant Certificate or the Warrant Agreement, no Warrant may be exercised unless, at the time of exercise, (i) a registration statement covering the shares of Common Stock to be issued upon exercise is effective under the Securities Act and (ii) a prospectus thereunder relating to the shares of Common Stock is current, except through “cashless exercise” as provided for in the Warrant Agreement.

The Warrant Agreement provides that, upon the occurrence of certain events, the number of shares of Common Stock issuable upon exercise of the Warrants set forth on the face hereof may, subject to certain conditions, be adjusted. If, upon exercise of a Warrant, the holder thereof would be entitled to receive a fractional interest in a share of Common Stock, the Company shall, upon exercise, round down to the nearest whole number of shares of Common Stock to be issued to the holder of the Warrant.

Warrant Certificates, when surrendered at the principal corporate trust office of the Warrant Agent by the Registered Holder thereof in person or by legal representative or attorney duly authorized in writing, may be exchanged in the manner and subject to the limitations provided in the Warrant Agreement, but without payment of any service charge, for another Warrant Certificate or Warrant Certificates of like tenor evidencing in the aggregate a like number of Warrants.

Upon due presentation for registration of transfer of this Warrant Certificate at the office of the Warrant Agent, a new Warrant Certificate or Warrant Certificates of like tenor and evidencing in the aggregate a like number of Warrants shall be issued to the transferee(s) in exchange for this Warrant Certificate, subject to the limitations provided in the Warrant Agreement, without charge except for any tax or other governmental charge imposed in connection therewith.

The Company and the Warrant Agent may deem and treat the Registered Holder(s) hereof as the absolute owner(s) of this Warrant Certificate (notwithstanding any notation of ownership or other writing hereon made by anyone), for the purpose of any exercise hereof, of any distribution to the holder(s) hereof, and for all other purposes, and neither the Company nor the Warrant Agent shall be affected by any notice to the contrary. Neither the Warrants nor this Warrant Certificate entitles any holder hereof to any rights of a shareholder of the Company.

Election to Purchase

(To Be Executed Upon Exercise of Warrant)

The undersigned hereby irrevocably elects to exercise the right, represented by this Warrant Certificate, to _________ shares of Common Stock and herewith tenders payment for such shares of Common Stock to the order of the Company in the amount of $_________ in accordance with the terms hereof. The undersigned requests that a certificate for such shares of Common Stock be registered in the name of _________, whose address is _________, and that such shares of Common Stock be delivered to _________ whose address is _________. If said number of shares of Common Stock is less than all of the shares of Common Stock purchasable hereunder, the undersigned requests that a new Warrant Certificate representing the remaining balance of such shares of Common Stock be registered in the name of _________, whose address is _________, and that such Warrant Certificate be delivered to _________, whose address is _________.

In the event that the Warrant has been called for redemption by the Company pursuant to Section 6.2 of the Warrant Agreement and a holder thereof elects to exercise its Warrant pursuant to a Make-Whole Exercise, the number of shares of Common Stock that this Warrant is exercisable for shall be determined in accordance with subsection 3.3.1(c) or Section 6.2 of the Warrant Agreement, as applicable.

In the event that the Warrant is a Private Placement Warrant that is to be exercised on a “cashless basis” pursuant to subsection 3.3.1(c) of the Warrant Agreement, the number of shares of Common Stock that this Warrant is exercisable for shall be determined in accordance with subsection 3.3.1(c) of the Warrant Agreement.

In the event that the Warrant is to be exercised on a “cashless basis” pursuant to Section 7.4 of the Warrant Agreement, the number of shares of Common Stock that this Warrant is exercisable for shall be determined in accordance with Section 7.4 of the Warrant Agreement.

In the event that the Warrant may be exercised, to the extent allowed by the Warrant Agreement, through cashless exercise (i) the number of shares of Common Stock that this Warrant is exercisable for would be determined in accordance with the relevant section of the Warrant Agreement which allows for such cashless exercise and (ii) the holder hereof shall complete the following: The undersigned hereby irrevocably elects to exercise the right, represented by this Warrant Certificate, through the cashless exercise provisions of the Warrant Agreement, to receive shares of Common Stock. If said number of shares of Common Stock is less than all of the shares of Common Stock purchasable hereunder (after giving effect to the cashless exercise), the undersigned requests that a new Warrant Certificate representing the remaining balance of such shares of Common Stock be registered in the name of _________, whose address is _________, and that such Warrant Certificate be delivered to _________, whose address is _________.

[Signature Page Follows]

Date:                 , 20__

Signature Guaranteed:

THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS, AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO RULE 17Ad-15 (OR ANY SUCCESSOR RULE) UNDER THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED).

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