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Understanding the Difference Between BIOS Boot Modes Legacy VS UEFI

BIOS boot modes, something that is so long standing in the IT industry which never changes, it had a single option which was the BIOS boot mode. The usual blue screen that only works with a keyboard and not a mouse, the blue screen that you have to access from the black screen on boot usually by repetitively tapping on either the F10, F2, F12, F1 or DEL key, depending on your motherboards manufacturer. Simple right? No. It’s an absolute nightmare.

But hey, we’ve got a newer and upgraded version of BIOS, and it’s called UEFI. UEFI was actually launched officially as a standard back in 2006 believe it or not. The time from when a standard is launched vs how quickly this moves throughout the IT hardware manufacturers is often measured in years, not months or days. So actually this is a fairly ‘new’ thing and many consumer hardware manufacturers only started to phase this technology into their systems around 2017.

The whole point of UEFI is the concept of Firmware-as-a-Service which is focused around extensibility rather than fixed approaches. What this means is that UEFI is designed to allow the utilisation of large disk partitions of over 2TB in size along with a modular design which enables both backwards and forwards compatibility.

Fundamentally the difference between BIOS and UEFI comes down to the link between the hardware and boot loader layer on your drives and bootable devices connected to your system. Think of this kind of like the ‘Construct Program’ in The Matrix – you can load whatever you want, given the constraints of the system.

In the real world what this means is that traditional BIOS systems are based on a more simplistic limited memory/capacity systems of computer chips. Whereas UEFI is capable of operating on systems that have more advanced hardware chips within their systems. Hardware and software are intricately linked. UEFI stands for Unified Extensible Firmware Interface.

One of the huge benefits from a user perspective is that within UEFI you can actually use your mouse to control the system rather than everything being keyboard driven in the Legacy BIOS system. Beyond that, you are probably never going to need to worry about these differences – that is until something doesn’t work as you expect in relation to a piece of hardware not booting correctly. This is where things are a bit messy and it’s going to take likely another decade until things fully iron their self out.

As a general rule of thumb, for modern hardware, just use UEFI to Boot. For older hardware or older operating systems, you may have to use Legacy Boot to get the machine to boot up successfully.

Rather than re-invent the wheel, here is a handy source of the core differences between Legacy Boot mode and UEFI Boot mode;

What is a difference between UEFI and Legacy Boot settings;

  • Legacy is traditional and very easy method which had worked absolutely fine so far.
  • UEFI is critical, 1709 was the first perfect OS which worked best with the OS.
  • Legacy has best in performance had minimum boot issues and easiest to install.
  • UEFI is now stable, but yet most of the IT tech do not now how to use this feature and correctly install the OS.
  • Legacy was safe and secure and very user friendly, it is just that you can select the boot device which you want to boot from and it search for Master Boot Record MBR and used to pick it up.
  • UEFI is market as more secure but there is no more security just that it supports TPM which enables Bitlocker and has extra headache to mention the EFI boot manager, which is no secure if you have access to BIOS and did it few times earlier just like Legacy.
  • Legacy has maximum partitioning size of 2 Terabyte.
  • UEFI has partitioning size of 9 Zetabyte which is huge.
  • Legacy can have 4 Primary Partition.
  • UEFI can have 128 Primary Partitions.
  • Legacy is good for loading 2 OS on same system.
  • UEFI is Great for loading more than 2 OS on the single system.
  • There are more differences and UEFI is way beyond the Legacy BIOS technology but it has not yet revealed its troe power.
  • Legacy uses Master Boot Record.
  • UEFI uses GUID Partition Table.
  • Legacy is traditional Firmware which interacts with Motherboard and OS.
  • UEFI is also just a Firmware with advanced options.
  • Microsoft New OS will no more support Legacy they have transformed now.
  • Microsoft stop support for Legacy OS after launch of 1709 WIndows update.
  • The last best Hard Drive supported by Legacy BIOS is SATA SSD.
  • The Last Best Hard Driver supported by UEFI is M.2 PCIE SSD Hard drive which does not work on Legacy BIOS.
  • Legacy Supports the SSCM in traditional way like you can enable PXE boot and select option to Boot From Network through LAN.

UEFI also supports and enable options to boot from traditional network which is IPV4 as well as IPV6. UEFI firmware is keeping all possibility of future options. To enable it you need to enable UEFI Network Stack which will give option for IPV4 and IPV6.

Election Day Ballot Box Results Using Agile Delivery Methodology

Imagine….. a situation where modern Agile Delivery Methodologies were applied to a very entrenched ‘way of working’ such as local elections that are happening right now throughout the UK. Well, let’s take a look at how this plays out so it’s easy to see how this can apply to your business and deliver value (aka. more efficiencies, sales, profitability etc. aka. £££) to your business faster. Who doesn’t want that, right?


There isn’t going to be a lot of talking in this blog post, more studying the image. Note the word value used below, think £££ ultimately. The core things to point out;

  • With Waterfall;
    • You only get to deliver any value right at the end, almost double the amount of time than with the Agile Delivery Methodology
    • The ‘Big Bang’ approach is heavily reliant on that single delivery method (aka. the car) working and not breaking down. If the car breaks down, the AA/RAC ( #ManyOtherProvidersAvailable 😉 ) have to be called out to save the day, wasting hours of time in the process
    • The focus from the delivery team, aka. the car driver and the Vote Counters, is high pressure, high speed, high quality, which naturally results in many errors (aka. Trump and his x+ days of recount nonsense that happened in the US recently). Why put your team under such pressure when you can adjust the way of working to deliver continually?
  • With Agile;
    • You get to deliver value within as little as 3 hours, and complete value is delivered in only 15 hours, almost 50% more efficient than waterfall
    • The ‘Phased Delivery’ approach is able to cope with issues with deliverability. Assuming different transport vehicles for the delivery of each ballot box, a break down in one doesn’t cause issues for the whole
    • The focus from the delivery team, aka. the car driver and the Vote Counters, is a low pressure, moderate speed, high quality, which naturally results in low errors. A low pressure environment leads to a happy workforce.

The main benefit is that we don’t need to wait up all night (seriously…. who does that?) to get the election results. Or in the case of recent US election results, several days.

There are so many analogies that I could go into with this blog post. But seriously, while this is a bit of fun at election time, start to think how you can approach Agile Delivery Methodologies to your organisation. The more you can chop down deliverables into tiny tiny pieces, not even large phases, then you will start to see productivity exponentially rise within your organisation when it comes to delivering value to your customers. We did a blog post a while back titled IT Project Delivery Achieving More by Doing Less which goes into a lot more detail about this topic. If in doubt, get in touch to see how you could supercharge the delivery of your organisation from an IT perspective with no more ‘Go Live Dates’.

How to Setup Let’s Encrypt on AWS EC2 Using Amazon Linux 2

Amazon Linux (aka. Amazon Linux 1) was straight forward to get Let’s Encrypt setup, it was a breeze and the documentation wasn’t too bad. I don’t know why Let’s Encrypt support for Amazon Linux 2 just isn’t where it needs to be, given the size and scale of Amazon Linux 2 and the fact that Amazon Linux is now an unsupported operating system. It’s likely because Amazon would prefer you to use their AWS Certificate Manager instead, but what if you just want a Let’s Encrypt certificate setting up with ease. Let’s take a look at how you get Let’s Encrypt setup on an AWS EC2 instance that is running Amazon Linux 2 as the operating system/AMI.



We’re assuming you’ve got Apache / Apache2 installed and set up already with at least one domain name. If you are using Nginx or other as your Web Server software then you’ll need to tweak the commands slightly.


How to Install Let’s Encrypt on Amazon Linux 2

Firstly, we need to get the Let’s Encrypt software installed on your Amazon Linux 2 machine, this is called Certbot. For those of you looking for the quick answer, here’s how you install Let’s Encrypt on Amazon Linux 2 along with the dependences;

yum search certbot

sudo amazon-linux-extras install epel

sudo yum install python2-certbot-apache

sudo yum install certbot-apache

sudo yum install mod_ssl python-certbot-apache

sudo certbot --apache -d


For those of you looking for a bit more information. There are a few fairly undocumented dependencies to get this working. So to get started you’ll want to install the dependencies for Let’s Encrypt on Amazon Linux 2 including;

  • Epel, aka. The Extra Packages for Enterprise Linux, from the Amazon Linux Extras repository
  • Python2 Certbot Apache using Yum
  • Certbot Apache using Yum
  • Mod_SSL, Python Certbot Apache using Yum

As it was a bit of a pain to get this configured, I’m fairly sure one of the above isn’t required, I just can’t recall which one that was.


How to Configure Let’s Encrypt on Amazon Linux 2 for a Domain

So now you’ve got Let’s Encrypt installed on Amazon Linux 2, it’s time to generate an SSL certificate for your domain that is hosted. For the purpose of simplicity we’re going to assume you’re running  very basic setup such as There are other nuances you need to consider when you have a more complex setup that are outside of the scope of this blog post.

sudo certbot --apache -d


What you’ll notice in the above is that we’re using Certbot and telling it that we’ve got an Apache Web Server behind the scenes and that we want to generate an SSL certificate for the Domain (-d flag)

Simply run that command and everything should magically work for you. Just follow the steps throughout.



The above steps should help you get setup using Let’s Encrypt on Amazon Linux 2 without much fuss. Amazon Linux 2 really does feel like it has taken a step back in places, Amazon Linux 1 had more up to date software in places, and easier to work with things like Let’s Encrypt. But hey. We can only work with the tools we’ve got on the AWS platform. Please leave any comments for how you’ve got along with installing Let’s Encrypt and getting it all set up on Amazon Linux 2, the good, the bad and the ugly.

How to Backup Your AWS Infrastructure Resources Such as EC2 and RDS Etc.

AWS. With great power comes with great responsibility. AWS doesn’t make any assumptions about how you want to backup your resources for disaster recovery purposes. To the extent that they even make it easy for you to accidentally delete everything when you have zero backups in place if you haven’t configured your resources with termination protection. So, let’s think about backups and disaster recovery from the start and plan what is an acceptable level of risk for your own setup.


Risk Appetite Organisationally and Application-ally

OK, that’s a made up word, but you get the gist. You need to assess your appetite to risk when it comes to risk, and only you can do this. You have to ask yourself questions and play out roll plays from “What would happen if a single bit of important data got corrupted and couldn’t be recovered on the Live system?” all the way through to “What would happen if the infrastructure running the Live system got hit by a meteorite?”. Then add a twist into these scenarios, “What would happen if I noticed this issue within 10 minutes?” through to “What would happen if I only noticed this issue after 4 days?”.

All of these types of questions help you to assess what your risk appetite is and ultimately what this means for backing up your AWS infrastructure resources such as EC2 and RDS. We are talking specifically about backups and disaster recovery here, not highly available infrastructures to protect against failure. The two are important aspects, but not the same.

As you start to craft your backup strategy across the applications in your corporate environment and tailor the backup plans against different categories of applications and systems into categories such as Business Critical, Medium Risk, Low Risk etc. then you can determine what this looks like in numbers. Defaults for frequency of backups, backup retention policies and such like.


How to Backup EC2 and RDS Instances on AWS Using AWS Backup

To start with the more common services on AWS let’s take a look at how we back these up and what types of configurations we have available to align out backup strategy with the risk appetite for the organisation and the application itself. The specific service we’re interested in for backing up EC2 and RDS instances on AWS is creatively called….. AWS Backup.

AWS Backup allows you to create Backup Plans which enable you to configure the backup schedule, the backup retention rules and the lifecycle rules for your backups. In addition, AWS Backup also has a restore feature allowing you to create a new AWS resource from a backup so that you can get the data back that you need and/or re-point things to the newly restored instance. Pretty cool really.

The first thing you want to do to get started is to create a Backup Plan. Within the creation process of your Backup Plan, you can configure all the items mentioned previously. Usually we’d walk through the step by step to do this, but really you just need to walk through the settings and select the options that suit your specific needs and risk appetite.

Below is a basic Backup Plan that is designed to run daily backups with a retention policy of 35 days, meaning we have 35 restoration points. You’ll also notice that instead of doing this for specific named resources, this is backing up all resources that have been tagged with a specific name.


Tagged Resources;


The tagged resource strategy using AWS Backup is an extremely handy way of managing backups as you can easily add and remove resources to a Backup Plan without ever touching the Backup Plan itself. Naturally you need a proper process in place to ensure things are being done in a standardised way so that you aren’t constantly hunting around trying to figure out what has been configured within AWS.


Running Backups

Once you have your Backup Plans in place, you can then start to see easily the backups that have been running, and most importantly if they have been successful or if they have failed.


Then you can drill into the details and see all of your restoration points within your Backup Vault and ultimately this is where you would restore your backups from if you ever need to do that;



Hopefully that’s a whistle stop tour of how to backup your AWS infrastructure resources such as EC2 and RDS on AWS using AWS Backup. The best advice I can give when you are implementing this in the real world is that you need to truly understand your IT landscape and create a backup strategy that is going to work for your business. Once you have this understood, clicking the right buttons within AWS Backup becomes a breeze.

Don’t do it the other way round, just creating random backups that don’t align with the business goals and risk appetites. You will end up in a world of pain. No-one wants to go reporting to the CEO….. IT: “Oh we only have backups for 7 days.” ….. CEO: “What?!?!?! We are legally required to keep records for 6 years! WTF!”. You get the gist.

This can be quite an enormous topic to cover, so here’s some further reading if you want to know more;

How to Import Zone Files into AWS Route53 DNS

So this isn’t quite as straight forward as it probably should be and the documentation from AWS is the usual, not great. So let’s cut through the nonsense and take a look at what you need to do so that you can quickly and easily get your DNS Zone Files and DNS Records migrated.


Assess Your Current DNS Provider, Zone Files, Domains and Nameserver Configurations

The first things you want to do before you start any kind of migration of your DNS over to AWS Route53 is the plan. Plan, plan and plan some more. Some of the nuances I came across with a recent DNS migration piece of work from DNS Provider X to AWS Route53 included some niggles such as vanity nameservers. The old DNS provider had things configured to and, then and pointed their nameservers to and which was quite a nice touch. This doesn’t quite work on AWS Route53 and I’ll explain that in a bit more detail in a moment. Another niggle that we came across that you need to plan properly and that is to make sure you have absolutely everything documented, and documented correctly. This needs to include for every domain at an absolute minimum things such as;

  • Domain name
  • Sub-Domains
  • Registrar (inc. login details, and any Two Factor Authentication 2FA steps required)
  • Accurate Zone File

The vast majority of people just have a Live version of their DNS Zone Files, which in itself is risky because if you had an issue with the DNS Provider X and you had no backup of the files, you could be in for a whole world of pain trying to re-build things manually in the event of a critical failure.


How AWS Route53 Manages Hosted Zones

So back to the point I mentioned earlier around vanity nameservers and why this doesn’t quite work in the way the old DNS Provider X worked.  When you create a new Hosted Zone within AWS Route53, Amazon automatically assigns 4x random nameservers of which you can see an example below;


What you will instantly notice here is that there are a lot of numbers in those URLs which should give you an idea of the complexity of the nameserver infrastructure behind the scenes on the Route53 service. What this also means is that because these nameservers are automatically generated you can’t configure two Hosted Zones to use the exact same nameservers to get the similar vanity nameserver setup explained earlier.

The reality is, this approach while is fairly common for complex setups, the majority of standard setups this isn’t an issue for. If you want to get vanity nameservers set up on AWS for a single domain, i.e. and etc. then you can do this if you wish.


Export Zone Files from your Old DNS Provider

The first step of this process is to export your Zone Files from your old DNS provider. What you will find from this process is that ever provider will export these slightly differently, and this highly likely won’t be in the format that Route53 needs when you import the Zone Files.


Create a Hosted Zone in Route53

This step is straight forward, just click the button.


Importing Zone Files to your Hosted Zone

As such, it’s time to prepare your Zone Files to be able to be imported into Route53 successfully. The format you need for your zone file import is as follows;



$TTL 1h        A   


Notice the couple of additional lines you need to add in which likely won’t be included from your export from your old provider. The above is just a very basic set of DNS entries. The reality is you will likely have 10 – 50+ DNS entries per domain depending on the complexity of your setup. One to keep an eye out on is that you may find certain record types don’t quite import seamlessly. Just a few niggles that I came across doing this included;

  • MX records required a 10 included, i.e. MX 10
  • DKIM (TXT) and SPF (TXT) records had to be re-generated and imported manually as the format just didn’t quite work for the automatic import for some reason.

And I’m sure you’ll come across a few issues along the way that I haven’t mentioned here.



Hopefully this guide on how to import Zone Files into AWS Route53 helps to clarify some of the niggles around using the Zone File Import feature. To reiterate around this process when you are doing this in a real situation, make sure you plan this properly, have clear checklists and processes that you can methodically work through to ensure things are working as you do them. These types of changes can have a significant disruption to live systems if you don’t implement these things correctly.