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I have had extremely variable luck with bootable USB sticks, and over time I have become puzzled and wonder what exactly is going on.
In threads such as this one and this one, it seems that I am not alone in having problems making bootable USBs on USB sticks that have already been made bootable. Some suggest that this has to do with Kingston drives, but I've had it with Samsung and SanDisk as well. Even stranger, most of the time I can get two or more bootable USBs out of one stick, but eventually sometimes, after having done it a lot, I get to a point where nothing short of zeroing, and even then, the USB will sometimes be a bit flaky afterwards, with various unpredictable problems arising around its use.
Have I simply had really bad luck with USB stick durability? Are USB sticks not really up to their advertised specs?
Do some disk utilities like Gparted or Startup Disk Creator take some kind of shortcut when overwriting blocks that look similar?
What could USB creation tools be doing that makes their work sometimes possible to delete and sometimes not?
Does this occur also when writing raw bootable images to the disk? – user1686 – 2019-06-10T03:55:17.447
You mean using dd? That isn't my usual method. I've heard people strongly advise for or against dd, but it all seems like superstition to me. – Stonecraft – 2019-06-10T04:18:36.980
Yes. It doesn't have significant disadvantages as long as the image already supports the desired boot method, and it's deterministic – it will always write the exact same data as the image has (regardless of the actual program, e.g. Linux dd vs Windows dd.exe vs Rufus "DD mode"), so if that still causes differences, you can be 100% sure it's not the program, and you can read back to another image and compare with original. – user1686 – 2019-06-10T04:28:22.623
What are the disadvantages? Speed? Otherwise, if it writes the same data, why should it matter? – Stonecraft – 2019-06-10T04:31:53.560
You rely on the image creator to include all boot methods needed (e.g. if the image is missing an EFI bootloader, the bootable-stick tools are often able to add that, but dd of course won't – although I notice that these "improvements" are quite fragile). You sometimes get a very strange-looking partition layout, due to the image having been built as a multipurpose CD+BIOS(+UEFI(+Apple)) image, and writing a 500MB image (with a 500MB main partition) to a 16GB stick prevents you from using the remaining 15.5GB for your own data, whereas using a bootable-stick tool creates a full-size partition. – user1686 – 2019-06-10T04:42:02.073
1Or in other words, the whole reason people sometimes want to use the bootable-stick making tools is that they do not always write the same data: they try to interpret the image's contents and re-do certain things in their own way. (I think I'll just post that as the final answer.) – user1686 – 2019-06-10T04:43:47.183
So basically, it is deterministic, but dependent on undocumented and ever-changing "features"? Seems like it would be a good idea to just stick to dd, and if the installer image in question does not include an EFI bootloader, take it up with the distro. – Stonecraft – 2019-06-10T04:45:02.883