SD Card Copier to an old RPi SD-card - not allowed?

[Bosse_B]

I want to copy my now working setup as a backup so I tried to use the RPi GUI.
The target SDcard is a 16 GB card whereas the live card is 32 GB but the used size is only 12 GB, so it should fit on a 16GB card.

I attached the target SD-card to my RPi4 using an USB memory reader and started "Accessories/SD Card Copier".
In the From Device box I selected EB1QT (/dev/mmcblk0) and in the target box I selected Mass Storage Device (/dev/sda), it was the only allowed item.
Now I thought that I was done and could use the Start button, but it is not enabled!
Is this because the target card contains a Pi image already? It is an old OSMC media center image I no longer use.

Since SD Card Copier purportedly does not need the same or larger size card only as large as will fit the actual data I thought I could re-use my old card.
But it seems like I am out of luck here.

Is there any way to erase the existing target SD card so SD Card Copier can use it???

THis is what I see in a terminal:

Code: Select all

sudo blkid
/dev/mmcblk0p1: LABEL_FATBOOT="boot" LABEL="boot" UUID="9F2D-0578" TYPE="vfat" PARTUUID="5e3da3da-01"
/dev/mmcblk0p2: LABEL="rootfs" UUID="efc2ea8b-042f-47f5-953e-577d8860de55" TYPE="ext4" PARTUUID="5e3da3da-02"
/dev/mmcblk0: PTUUID="5e3da3da" PTTYPE="dos"
/dev/sda1: UUID="E41A-EA0D" TYPE="vfat" PARTUUID="00095b1c-01"
/dev/sda2: UUID="bb3ea5f8-ef8b-4df3-9e6e-520f330875d8" TYPE="ext4" PARTUUID="00095b1c-02"

sudo lsblk -o UUID,NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL,MODEL
UUID                                 NAME        FSTYPE  SIZE MOUNTPOINT LABEL  MODEL
                                     sda                14.9G                   Storage_Device
E41A-EA0D                            ├─sda1      vfat    243M                   
bb3ea5f8-ef8b-4df3-9e6e-520f330875d8 └─sda2      ext4   14.6G                   
                                     mmcblk0            29.8G                   
9F2D-0578                            ├─mmcblk0p1 vfat    256M /boot      boot   
efc2ea8b-042f-47f5-953e-577d8860de55 └─mmcblk0p2 ext4   29.6G /          rootfs 

[Bosse_B]

Problem solved!
I went back and repeated the drive selections and it seems like I have to select the target twice for it to be recognized!

[Bosse_B]

EXCEPT it takes an enormously long time!
It has been running now for 35 minutes and the progress bar is like at the 20% mark! So I am looking at more than 2.5 hours of copy time.
Is this normal?
When I used the same USB SD reader to make the original from the Raspbian download it took probably only 5+ minutes to complete with the full image of Buster. That was on Windows using Etcher.
Strange.

Does it matter if I do this through VNC? Or must I have a direct monitor connection for this?
I tried to move the SD Card Copier window on screen but then the progress bar part detached from the main window and could not be moved...