Image backup and writing to a new microsd.

Efriim

RetroPie 4.4.14
Rpi3b+
USB boot mode enabled.

Hi, I'm going to transfer my current 64gb image to a new micro-sd 64gb.
I'm thinking I will use win32disk imager, to read..................... and then write.

But I'm meditating on making a usb boot (only works with microsd removed?) having the unformatted new microsd in the rpi, and using a usb microsd adapter to plug in the old microsd, and use a direct write (dd if=/dev/sdb of=/dev/mmcblk0).

Does anyone want to tell me why I shouldn't do this? Is there a better way to make that work, possibly creating the partitions on target device first, and writing those individually?
What will happen if the target drive is a few bytes short? Is there a better operation that can be done on linux? What about on windows, is there a better program to write sd image?

mitu

@Efriim said in Image backup and writing to a new microsd.:

But I'm meditating on making a usb boot (only works with microsd removed?) having the unformatted new microsd in the rpi, and using a usb microsd adapter to plug in the old microsd, and use a direct write (dd if=/dev/sdb of=/dev/mmcblk0).

This will overwrite your SD card with the contents of /dev/sdb (the USB). The order is if = Input File, of = Output file.

Does anyone want to tell me why I shouldn't do this? Is there a better way to make that work, possibly creating the partitions on target device first, and writing those individually?

You can use rsync to copy the data from your existing system to the new one. There's already an utility for that: rpi-clone.

What will happen if the target drive is a few bytes short? Is there a better operation that can be done on linux? What about on windows, is there a better program to write sd image?

The if target is a few bytes short, you'll get an I/O error from dd.

Efriim

@mitu
The device setup I was thinking would be like this on the raspberry pi
USB1: Usb image boot, raspbian? smaller.
Micro-SDslot: unformatted new microsd (the target of the image write)
USB2: Usb microsd adapter (the source of the image write)

rpi-clone; and I thought I made it sound confusing.