Methods, apparatus, systems, and articles of manufacture to perform a pseudo-S3 protocol to update firmware and/or activate new firmware with a warm reset are disclosed. An example apparatus includes an advanced configuration and power interface (ACPI) to: initiate a pseudo-sleep event in response to identifying a firmware update; and assert a power button event, the power button event to cause an operating system (OS) to prepare to enter into a sleep state; a basic input/output system (BIOS) to: initiate a warm reset in response to the OS preparing to enter the sleep state, the warm reset to update firmware according to the firmware update; and transmit a wake vector to the OS to continue operation.