A bootable flash drive only lives once. Why?

Question

linux

Good evening. I have noticed more than once - I make a bootable USB flash drive, from Linux and with Linux, I do it with the help of dd. I just copy the .iso image. The flash drive boots and works great. But only once. And the second time - does not want to boot, writes "DISK BOOT FAILURE". As if something after the first boot overwrites the bootloader on it. I don't understand what is happening. I make a USB flash drive in a similar way through dd a second time - and again it is enough for one download. Laptop with secure boot but disabled.

Answer 1

I do it with dd.

Don't do it with dd.
It may well be that after that it is necessary to restore it: restore the flash drive .

Answer 2

dd is an extremely low-level thing. A backup taken by him is guaranteed to be restored only to the same device (or to a device with exactly the same parameters). Flash drives - even of the same capacity - always differ slightly in parameters. dd don't care - he restored everything. But the loader can "fix". If there is a gui, you can use unetbootin - it is also available under linux.