Finally! Raspberry PI 4 boot from SSD, no MicroSD required!

Hi all, I just viewed this good news.

Official announcement:

More info:

Andreas Spiess video:
and cheatsheet:


EDIT 2020/05/22 just to anticipate your next question:
Q: Does it work for HassOS?
A: Not jet (HassOS v3.13 and v4.6rc), but there is a partial solution which gives most of the benefits, just skip to reply n.32


Interesting for sure and probably what we all think we want. But what is the practical gain ? Counting, I have 7 * R Pi undertaking various tasks and I’m not sure any would benefit particularly. Perhaps it will be useful in Home Assistant.

I do have a spare SSD, so I’m looking for an excuse to buy another R Pi :smile:

SSD has a greater write endurance than SD == less chance of corruption.


Yeah good they’ve finally done it, though might wait until its production released. Currently already booting from SD to SSD, so I’m already getting the benefit of the SSD.


But what is the practical gain ?

SSD has a greater write endurance than SD == less chance of corruption.

And an SSD is blazing fast compared to SD and USB thumb drives.

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You won’t be seeing SATA III speeds through the USB port though.

Running Hassio we must wait an update of the supervisor to get this?

USB = 5GB/s
Sata 3 = 6 GB

While USB is slower, there’s not a huge difference, and I did notice a nice speed increase on Raspbian going from an SD to SSD.

Hahaha. Oh Dear. USB3 has an upper limit of 5Gb/s (notice the small b), however to qualify as USB3 all you have to do is be faster than USB2 (480Mb/s). Now, while the pi4 has made a substantial jump in USB throughput it is only about half of what SATA III throughput is capable of in Bytes/s (600MB/s).

If you’re on an older model pi, a SATA III capable SSD would be a waste of money. (Though there may be other advantages like caching).

b = bit
B = byte (8 bits).


Here’s the same data about SSD on USB3 on Pi4, along with uSD performance.
So you’re still better off with SSD than uSD from both a speed and wear perspective.

SDStorage uSDStorage

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Yeah my comment wasn’t about SD vs SSD speeds. It was about SATA being limited by USB throughput.

And then the fact that this is not true:

There’s a big difference. About 50% in this case. It all depends on the USB3 chipset. Some barely qualify as USB3.

It wasn’t referring to the potential of USB3 and how the Pi4 performs, more the comparison of SSD against uSD.

As for USB3 against SATA3, it is 5Gb/s against 6Gb/s, not the 6GB/s previously mentioned. But yes highly dependant on drivers, chipsets and the like.

You can also benefit from things like RAID storage on USB, something you can’t do with uSD.

An update of HassOS (the underlying OS for a straight-from-image running Home Assistant) is required. So yes we probably have to wait a bit.

No, That’s the point, it boots from where the boot loader is.
People are already booting from SSD’s on Pi3’s
Now we can do it from a Pi4

Yeah, though Tom is right those graphs really put it in perpective (paraphrase from Animal Farm) : -
USB3 Good, SSD under USB3 Better

@Mutt I didn’t succeed on a RasPI 4 “prepared” (BOOT_ORDER=0xf41) and successfully tested with Raspbian Lite booted via SSD (no uSD).

Booting HassOS 3.13 32bit via SSD, the RasPI4 is stuck on a boot-loop, as shown in the picture below. Same result with HassOS 4.6rc, both 32bit and 64bit versions.

The same HassOS 3.13 boots regularly via uSD on the same RasPI4.

Any hint?

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Bugger !


I’ve just spent 2 hours digging out a spare Pi 4, a power supply, casing up a spare SSD and now you drop this on me.


You’ve done everything I would have done, I haven’t a clue where to go from there
I’m not blaming you, I’m not blaming anyone, I just assumed it would work with Pi4 HassOS

Well I suppose that gives me a couple of days free time (not playing with a new Pi 4 HA test and more time … ) to continue with the COVID19 chores the wife wants me to do.

Well it looks like we’ll have to wait for the official EFI from RPF and then wait as @maurizio53 said but for a Pi 4 HassOS to catch up with that.
But now there is light at the end of the tunnel.

Thanks for your original Post :+1:

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No clue, HassOS partition hassos-kernel contains only the file zImage, no config.txt or the like here.

I hope this will be considered a killer feature to promote HassOS :wink:

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Meanwhile we can stick with this solution to boot the RasPI4 via SD and have the data partition on the SSD.
Tomorrow I will try it.

I did this and it works perfect. I am will jump to no-SD when the function has more time to bake.