Re: Problem reading data from CD-ROM, failed to copy.

[john doe <johndoe65534@mail.com>]

On 1/31/2018 12:11 AM, James Byrnes wrote:
> This dilemma is a result of a hackjob, something that normally shouldn't be
> able to run: loading Linux on a $59 WinBook TW-700.
>
> I downloaded a copy of debian-9.3.0-amd64-netinst via torrent and extracted
> it to a bootable USB. I had to replace bootx64.efi with bootia32.efi as
> this tablet uses a 32bit EFI while also having a 64bit OS, otherwise it
> would not boot from USB.
>
> Halfway through load installer components from CD, the process fails to
> read the USB and crashes without ability to recover.
>
> Since this tablet only has 1 USB port, I am relegated to using a hub for
> keyboard input.
>
> I believe this issue stems from the fact that the iso was downloaded via
> torrent, and the data could have possibly be corrupted. Hopefully I'll be
> able to obtain a copy from dead-slow HTTP download (forced to use 128kb/s
> cellular data for download).

To insure that the
iso is not corrupted you need to checksum the iso using sha512sum 
utility and verify that iso using gpg.

- If the checksum is successful your iso is not corrupted.
- If verifying the signature is successful your iso has not been 
tempered with.

Here's what I wrote earlier on the list:

To checksum a file you will need to use the corresponding checksum utility:
md5sum for MD5SUMS
sha1sum for SHA1SUMS
sha256 for SHA256SUMS
sha512sum for SHA512SUMS

On the download page for the desired iso file you have also 'SHA512SUMS' 
and 'SHA512SUMS.sign'.
You download both files using for instance 'wget'.

The first step is to verify the signature in 'SHA512SUMS' using 'gpg 
--verify *.sign'.
When you see 'good signature from ...', you have successfully verified 
the iso.

To checksum SHA512SUMS you would do:

$ sha512sum -c SHA512SUMS 2>&1 | grep -i ok

If you see something ending with ': ok', you have successfully 
checksummed the iso.

--
John Doe