tomlecong,

Here is some information to try and resolve the issue. Let us know if it resolves the issue.

The engineering department has identified that this is due to the computer not being turned on correctly.

Steps to re-create the fault:

The keyboard backlight does not come on at the first press of the power button.

You press the Power button multiple times.

This triggers an abnormal boot behavior.

The computer goes into a BIOS Auto-Recovery loop.

How to Avoid the BIOS Auto-Recovery Loop

Connect the Power adapter and press the power button once.

If the keyboard backlight does not illuminate, leave the computer alone for at least 5 seconds and then try the power button again
 
Update to the latest BIOS version available for your computer to resolve this issue. To download and install the latest BIOS:

Warning: Dell recommends disconnecting any devices like external hard disk drives, printers, scanners before updating the BIOS.
 
Warning: Dell laptops must have the battery installed and charged to at least 10% before you begin the BIOS update. Dell recommends connecting the laptop to AC power before proceeding with the update process.

Browse to the Dell Drivers and Downloads page for your computer:

Latitude 5420

Select the Operating System.

Under Category, select BIOS.

Locate the latest:

Dell Latitude 5420 System BIOS (Version 1.8.0 or newer).

Click Download and save the file to your computer.

Open File Explorer and browse to the location where the downloaded file is saved.

Double-click the BIOS setup file and follow the on-screen instructions to complete the installation process.

Your computer will restart as part of the installation process.

tomlecong,

Following up to see if the information provided resolved the issue?  Let us know.

Dell-Jesse L

tomlecong,

Following up to see if the information provided resolved the issue?  Let us know.

Dell-Jesse L

Hard to believe on a newer system that the CMOS battery is weak or bad but possible. Try changing the battery on one of the systems and watch for any further errors compared to the other laptops. Also possible that a virus is causing the problem. One last thought but a long shot, is it possible that the systems are simply being turned off without a proper shutdown though that usually will corrupt Windows files.

It's 2021 model laptop. It's completely new. We never had any problem like this with older models. We have 16 of them and all of them have the same problem. I don't know what's the cause. I hoped that somebody had the same issue and solution.

I've seen this a couple times now. It just get stuck in the loop and using a fat32 flash doesn't change anything. It doesn't even try to look. So what I have been doing is disconnecting the batteries, normal and cmos, waiting 15 minutes. Then reconnecting and powering back on. Now I can get into bios and set date and time, not stuck in the auto-recovery loop.

I've had similar problems with quite a few of our 5420 models.

When they're turned on it looks like it begins some sort of display selftest where the screen flashes in different colors for some time and then it turns off.

In a few cases we've been able to solve it by pressing CTRL+ESC down while connecting the power adapter but in most cases it's required a motherboard replacement.

In one case Prosupport suggested that we make a USB flash drive with a recovery BIOS on it and then perform the CTRL+ESC procedure with that USB flash drive inserted. Only problem is that there is no recovery BIOS for the Latitude 5420 model on Dells homepage - it doesn't exist for this specific model...

I think our current failure rate on this model is around 10% and we've purchased 100+ of them.

They've been purchased on several different orders over the last 4-5 months so I don't believe that it's a problem with a specific shipment of sub components.

Worst problem is that Dell doesn't have the spare parts to replace the motherboards. In one case we were told to expect 2-3 months repair time - so much for paying for Prosupport - that only speeds up the process until it's determined that a repair is needed - after that you're stuck if the spare parts are not available.

Regards, Martin

Welcome to the Dell Community @gaegler 

Please try this.

Hold down the " D " key and power-on.

This should start Dell's "BIST" Built In Self Test.

Is that the same thing you are seeing???

Best regards,

U2

No, it's not. it looks like this.

The only thing that helps is disconnecting the power adapter, turning off the device, holding CTRL + ESC and connecting power adapter. I can reflash BIOS then.

This is not normal. It only happens at this model.

Welcome to the Dell Community @tomlecong 

Sorry but the question was directed towards @gaegler  not you.

But thank you for clarifying what type of of loop it is.

Now someone else may have something to add.

The information "should" help Dell find a solution.

Best regards and good luck,

U2