Hi Peter & Philippe, On Tue, Feb 18, 2020 at 11:05 AM Peter Maydell <peter.mayd...@linaro.org> wrote:
> On Tue, 18 Feb 2020 at 06:46, Philippe Mathieu-Daudé <phi...@redhat.com> > wrote: > > IIRC from the specs, cards are block devices and the only alignment > > required is the size of a block (512KiB for your 4GiB card). > > Isn't there something related to erase blocks too, which impose > a larger granularity than just a single block? > > Anyway, in general the backing image for an SD card device > needs to be exactly the size of the SD card you're emulating, > because QEMU needs somewhere it can write back the data > if the guest decides to write to the last block on the card. > So short-length images generally don't work (true for all > block devices, not just SD cards, I think). This often bites users > if they're using some distro "here's a disk/sd card image file" > where the expected use with real hardware is "dd the image > file onto the SD card". > Yes, the description you gave here is indeed the issue. And unfortunately in this particular case, the distro did not give a very understandable diagnostic error message. Kind regards, Niek > > thanks > -- PMM > -- Niek Linnenbank
