Dynamic transaction card (120, 200, 300) comprising: - a EuroPay-MasterCard-Visa-processor (126, 212, 312, 812) as EMV-processor storing existing firmware and version data associated with the existing firmware; - an EMV plate connectively coupled to the EMV processor (212,...); - a bootloader (222, 322); and - an input/output interface for receiving a first portion of a firmware update from a firmware provider system via a secure terminal and a second portion of the firmware update from a mobile device; - an applet (126b, 208, 308) comprising instructions that when executed, cause the EMV processor (212,...) to perform a checksum validation; and - data storage storing the first portion of the firmware update and the second portion of the firmware update, the first portion of the firmware update and the second portion of the firmware update forming a total firmware update, wherein one of the first portion of the firmware update or the second portion of the firmware update comprises a first checksum, wherein for validating the total firmware update on the dynamic transaction card (120,...) the following functions are implemented therein: - calculating, using the EMV-processor (212,...), a second checksum associated with the total firmware update; - comparing, using the EMV-processor (212,...), the first checksum to the second checksum; and - validating (620,624) the total firmware update upon determining that the first checksum and the second checksum are equal; wherein: - the bootloader (222, 322) is configured to receive, once the total firmware update is validated, a boot signal from the secure terminal or the mobile device, and to use the bootloader signal to validate the bootlader and determine whether the existing firmware is valid, load and execute the total firmware update to overwrite the existing firmware; and - the EMV-processor (212,...) is configured to store and use the total firmware update in response to the bootloader (223, 322) loading and executing the total firmware update. - a EuroPay-MasterCard-Visa-processor (126, 212, 312, 812) as EMV-processor storing existing firmware and version data associated with the existing firmware; - an EMV plate connectively coupled to the EMV processor (212,...); - a bootloader (222, 322); and - an input/output interface for receiving a first portion of a firmware update from a firmware provider system via a secure terminal and a second portion of the firmware update from a mobile device; - an applet (126b, 208, 308) comprising instructions that when executed, cause the EMV processor (212,...) to perform a checksum validation; and - data storage storing the first portion of the firmware update and the second portion of the firmware update, the first portion of the firmware update and the second portion of the firmware update forming a total firmware update, wherein one of the first portion of the firmware update or the second portion of the firmware update comprises a first checksum, wherein for validating the total firmware update on the dynamic transaction card (120,...) the following functions are implemented therein: - calculating, using the EMV-processor (212,...), a second checksum associated with the total firmware update; - comparing, using the EMV-processor (212,...), the first checksum to the second checksum; and - validating (620,624) the total firmware update upon determining that the first checksum and the second checksum are equal; - calculating, using the EMV-processor (212,...), a second checksum associated with the total firmware update; - comparing, using the EMV-processor (212,...), the first checksum to the second checksum; and - validating (620,624) the total firmware update upon determining that the first checksum and the second checksum are equal; - the bootloader (222, 322) is configured to receive, once the total firmware update is validated, a boot signal from the secure terminal or the mobile device, and to use the bootloader signal to validate the bootlader and determine whether the existing firmware is valid, load and execute the total firmware update to overwrite the existing firmware; and - the EMV-processor (212,...) is configured to store and use the total firmware update in response to the bootloader (223, 322) loading and executing the total firmware update.