[Amended] Material event report (equity acquisition)

What happened

Decision to Acquire Equity and Investment Securities of Another Company 6.1 Ryuk-Il C&S Co., Ltd. Amendment Report (Filing), August 5, 2026

1. Disclosure document being amended: Material event report (decision to acquire equity and investment securities of another company) 2. Original filing date of the document being amended: June 19, 2024 3. Amendment details

Item: 2. Details of acquisition, change of payment form and acquisition amount by agreement Before: Acquisition amount (KRW) (A): 11,500,320,000; Ratio to total assets (%) (A/B): 29.39; Ratio to equity capital (%) (A/C): 44.11 After: Acquisition amount (KRW) (A): 6,500,320,000; Ratio to total assets (%) (A/B): 16.61; Ratio to equity capital (%) (A/C): 24.93

Item: 7. Payment of transaction consideration Before: 1. Form of payment: Cash payment, and payment in kind following issuance of Ryuk-Il C&S's Series 3 bearer, interest-bearing, unsecured, privately placed convertible bonds. 2. Payment timing and amounts, Down payment (KRW 1,150,032,000): June 18, 2024 (contract execution date), including KRW 300,000,000 of due-diligence deposit already paid; Balance (KRW 10,350,288,000): July 10, 2024, KRW 5,350,288,000 in cash and KRW 5,000,000,000 by payment in kind following issuance of convertible bonds. After: 1. Form of payment: Cash payment. 2. Payment timing and amounts, Down payment (KRW 1,150,032,000): June 18, 2024 (contract execution date), including KRW 300,000,000 of due-diligence deposit already paid; Balance (KRW 5,350,288,000): July 10, 2024, paid entirely in cash.

Item: 15. Other important matters related to investment judgment, 3) Details of "6. Transaction counterparty" Before: Lee Don-won: 1,600,000 shares, 75.24%, transaction price KRW 9,312,000,000, price per share KRW 5,820; Lee Jung-gyun: 376,000 shares, 17.68%, KRW 2,188,320,000, KRW 5,820; Total: 1,976,000 shares, 92.93%, KRW 11,500,320,000, KRW 5,820. After: Lee Don-won: 1,600,000 shares, 75.24%, KRW 5,263,417,004, KRW 3,290; Lee Jung-gyun: 376,000 shares, 17.68%, KRW 1,236,902,996, KRW 3,290; Total: 1,976,000 shares, 92.93%, KRW 6,500,320,000, KRW 3,290.

Newly added (item 8): The Company filed a civil lawsuit against the counterparty seeking return of part of the purchase price on grounds including an inventory shortfall at the acquired company after closing; on August 5, 2026, the Company and the counterparty reached a mutual settlement under which the counterparty transferred to the Company all rights relating to the convertible bonds (including principal and interest), resulting in the change to the acquisition amount.

Material Event Report / Exchange reporting obligation matter To: Financial Services Commission / Korea Exchange June 18, 2024 Company name: Ryuk-Il C&S Co., Ltd. CEO: Koo Ja-ok Head office: 2001, Dong 2, Ace High-Tech City, 775 Gyeongin-ro, Yeongdeungpo-gu, Seoul (Phone) 02-2659-1116 (Website) http://www.61cns.co.kr Preparer: (Title) Managing Director (Name) Park Tae-ho (Phone) 02-2136-5733

Decision to Acquire Equity and Investment Securities of Another Company 1. Issuing company Company name: Combus Tech Co., Ltd. Nationality: Republic of Korea Representative: Lee Don-won Capital stock (KRW): 1,251,455,000 Relationship with the Company: - Total shares issued (shares): 2,126,439 Main business: Smart edu-tech and artificial intelligence platform business Acquisition of new shares via third-party allotment within the last 6 months: Not applicable 2. Details of acquisition Number of shares acquired (shares): 1,976,000 Acquisition amount (KRW) (A): 6,500,320,000 Total assets (KRW) (B): 39,131,561,317 Ratio to total assets (%) (A/B): 16.61 Equity capital (KRW) (C): 26,069,780,405 Ratio to equity capital (%) (A/C): 24.93 3. Number and ratio of shares owned after acquisition: 1,976,000 shares; 92.93% 4. Purpose of acquisition: Pursuit of new business 5. Expected acquisition date: July 10, 2024 6. Transaction counterparty Company name (individual name): Lee Don-won and 1 other (specially related person) Capital stock (KRW): - Main business: - Head office address: Singil-dong, Yeongdeungpo-gu, Seoul Relationship with the Company: - 7. Payment of transaction consideration 1. Form of payment: Cash payment 2. Payment timing and amounts: Down payment (KRW 1,150,032,000): June 18, 2024 (contract execution date), including KRW 300,000,000 of due-diligence deposit already paid; Balance (KRW 5,350,288,000): July 10, 2024, paid entirely in cash 3. Method of financing: Own funds 8. External appraisal External appraisal conducted: Yes Basis and reason: 1. Basis: Financial Investment Services and Capital Markets Act Article 161 and its Enforcement Decree Article 171-2. 2. Reason: To serve as reference material for judging the appropriateness of the acquisition price and as an attachment to the material event report External appraisal institution: Sunghyun Accounting Corporation External appraisal period: May 21, 2024, June 14, 2024 External appraisal opinion: Adequate 9. Board resolution date (decision date): June 18, 2024 - Independent (outside) director* attendance: Present (persons) 1 / Absent (persons) - - Auditor (audit committee member who is not an independent (outside) director*) attendance: Present 10. Backdoor listing status: No - Plan for third-party allotment capital increase within the next 6 months: Yes 11. Whether the issuing company (other company) meets backdoor listing requirements: No 12. Subject to Fair Trade Commission reporting: Not applicable 13. Whether a put option or similar contract has been entered into: No * For listed companies, "independent director"; for unlisted companies, "outside director" 14. Plans for future corporate restructuring: As of the date of this report, the Company has not decided any specific plan for corporate restructuring. 15. Other important matters related to investment judgment 1) The "total shares issued" in "1. Issuing company" is as of the disclosure filing date. 2) The "total assets" and "equity capital" in "2. Details of acquisition" are based on the Company's 2023 year-end consolidated financial statements. 3) Details of "6. Transaction counterparty": Lee Don-won, 1,600,000 shares, 75.24%, KRW 5,263,417,004, price per share KRW 3,290; Lee Jung-gyun, 376,000 shares, 17.68%, KRW 1,236,902,996, KRW 3,290; Total, 1,976,000 shares, 92.93%, KRW 6,500,320,000, KRW 3,290. 4) In the [Summary Financial Status of Issuing Company] below, the current year is based on 2023 separate financial statements, the prior year on 2022 separate financial statements, and the year before that on 2021 separate financial statements. 5) For other details, please refer to the attached "Opinion of External Appraisal Institution." 6) Securing the minority shareholders' stake in Combus Tech Co., Ltd. will proceed separately. 7) The above disclosure content may change depending on future developments, and any changes will be disclosed by amendment. 8) The Company filed a civil lawsuit against the counterparty seeking return of part of the purchase price on grounds including an inventory shortfall at the acquired company after closing; on August 5, 2026, the Company and the counterparty reached a mutual settlement under which the counterparty transferred to the Company all rights relating to the convertible bonds (including principal and interest), resulting in the change to the acquisition amount. ※ Related disclosures: -

[Summary Financial Status of Issuing Company] (unit: KRW thousand) Current year: Total assets 25,852,496; Total liabilities 17,734,791; Total equity 8,117,704; Capital stock 1,251,455; Revenue 30,253,097; Net income 1,548,589; Audit opinion Adequate; External auditor Induk Accounting Corporation Prior year: Total assets 24,411,991; Total liabilities 17,622,299; Total equity 6,789,691; Capital stock 1,251,455; Revenue 30,130,591; Net income 1,009,510; Audit opinion Adequate; External auditor Barum Accounting Corporation Year before that: Total assets 12,667,190; Total liabilities 7,469,081; Total equity 5,198,108; Capital stock 1,251,455; Revenue 19,359,469; Net income 996,624; Audit opinion Adequate; External auditor Barum Accounting Corporation

[Matters concerning the transaction counterparty] 1. Basic information: Name (entity) Lee Don-won and 1 other; Nationality Republic of Korea; Address (head office, down to town/township level) Singil-dong, Yeongdeungpo-gu, Seoul; Occupation (business description): - - Largest shareholder/CEO/representative executive officer status and financial condition (where the counterparty is a corporation): Not applicable (all fields "-") 2. Relationship between the Company or its largest shareholder/officers and the counterparty: - 3. Transaction history over the last 3 years (excluding routine transactions): Current year, payment of KRW 300,000,000 due-diligence deposit; prior year -; year before that -