Hello all,

Some time ago I found on option to write an sdcard image from the contents of a
 zip file, without writing it to a local FAT formatted storage media.
I forgot to save that interesting option ;-(.
That's why I come here to ask you all.

So we have a zip file:

raspios-buster.zip  2.5 GiB

with as contents a SDcard image:

raspios-buster.img  6.9 GiB

So the question is, "How can I extract and write that image to the microSDcard
in one go without writing that image to the local FAT disk temporarly,
as it is FAT formatted, or has less room for another 7 GiB."
Every one knows that FAT partitions can only handle files smaller than 4 GB.
So extracting that Raspbian Buster image of 6.9 GiB first is a problem there.
I am sure it could be done in one go, but the question is how?

Can anyone give me the right syntax for the combined dd- and extracting- and
pipe-command?
I.e. extract the zip and give that output via piping to the dd writing command.

Very recent I tried to write the already extracted 7 GiB image from a 64 GB
EXT4 Linux partition on an USB3A stick with a USB2-SDcardwriter at the other
USB3A port of my 2019 Pi 4B 4GB.
Normally it writes at about 8 MB/s on the Pi 3B+ with a USB2A SDcardwriter,
but now on the Pi 4B it wrote about 16 MB/s, that's double the speed !

Are there already USB3A SDcard reader/writers?
Then the writing speed wil increment much more I think.

A third option could be making a RAM disk of 7 GiB on my new Pi 4B 8GB.
But I do not know how to do that, and if that solution could work too?
Then I could extract that rasbian SDcard image from the zip file first to
the big ramdisk, and after that write it to a fresh microSDcard.
But that solution could only be temporarly available, as the RaspiOS image
is still growing every year, and then the 7 GB RamDisc would be soon to
small for it.
So I would like more the on the flow extracting and writing method as
mentioned above of which I do not know the exact syntax,
That's why I aks here.
Thank you for reading and answering my questions.

Greetings from Henri at Arnhem.nl.

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