Magnachip Semiconductor (MX) 10-K/A 2020 FY Annual report (amended)

Exhibit 31.4

CERTIFICATION OF PRINCIPAL FINANCIAL OFFICER

PURSUANT TO

SECTION 302 OF THE

SARBANES-OXLEY ACT OF 2002

I, Young Soo Woo, certify that:

1. I have reviewed this annual report on Form 10-K/A of Magnachip Semiconductor Corporation;

2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report.

Dated: April 30, 2021

/s/ Young Soo Woo

Young Soo Woo

Chief Financial Officer

(Principal Financial Officer)