Dell E6420 older BIOS A05 A08 need in order to install latest BIOS

Hello all,

Just bought this laptop from ebay and I am looking to upgrade my current BIOS (A03) to the latest one (A23). But I am not able to install this latest BIOS (A23) unless my current BIOS is (A05). I follow the instruction on Dell support site and trying to download (A05) but it does not show anything in the links.

Where can I find this (A05) BIOS for my laptop?

Here is the instruction provided by Dell Driver and Download:

Note:

1. Please note that if the A04 or before A04 BIOS is currently installed on your system, you must first update to A05 BIOS and then flash to the latest A-rev BIOS.
A05 link: www.dell.com/.../DriverDetails

2. Please note that if the A05 or after A05 BIOS and before A08 is currently installed on your system, you must first update to A08 BIOS and then flash to the latest A-rev BIOS.
A08 link: www.dell.com/.../DriverDetails

Looking forward for your assistant and thanks in advance for all your help.