So I wanted to get a couple of SanDisk 32 GB micro SD cards and was in a hurry and want to Walmart. They didn’t have the SanDisk devices I usually get, but they had their own brand (ONN). They are the same class and speed as the SanDisk.
I tried to burn the ONN devices from a backup image but the write failed (twice). Then I noticed the capacity of the ONN devices is slightly smaller than the SanDisk devices (31.7 GB vs 31.9 GB). Does that difference matter? The image was from a SanDisk device.
Does anyone have experience with the ONN devices? I was able to burn a basic Bookworm image on the ONN device and it does seem to run ok on the RPi.
After looking into this some more, I found the following: all micro SD disks marked with a size of say, 32 GB do not have the same capacity. (Some people probably already knew this). However, if two SD disks are from the same manufacturer with the same markings , they will have the same capacity. At least I found this to be the case for a small sample of SanDisk and ONN micro SD disks that I looked at.
For SanDisk I have two different versions of the 32 GB micro SD disks. One version has red/gray color marked “Ultra A1” , the other version is white/gray color and just marked “Ultra”. The white/gray version has less capacity than the red/gray version. The ONN micro SD disks had less capacity than both SanDisk devices.
It turns out that I had been backing up between a couple of SanDisk red/gray devices and so can’t backup to anything but those. I would have to reduce the image size by using rip-clone as mentioned in other threads to backup to the smaller capacity SanDisk or ONN devices.
Simply format each mSD main partition the same, smaller size using a tool such as AOMEI Partition Assisstant (freeware). This will leave a few unused sectors on the larger mSD cards, but it makes backups much easier.
Well that would be good advice if I were starting from scratch (and use Windows). However, for now I’ll just make sure that whatever devices I use for backup of any given processor are exactly the same make and model as the original device for that processor.
