[OSGeoLive] problem with bootable usb stick creation via dd

[Ben Caradoc-Davies]

I was able to boot 12.0beta3 with both legacy (BIOS/MBR) and UEFI from a 
thumb drive written with:

dd if=osgeolive-12.0beta3-amd64.iso of=/dev/sdX bs=8M; sync

Everything seemed to work fine.

I am using a recent Asus UEFI BIOS with Legacy boot support enabled. The 
thumb drive is an ancient Intel 8 GB USB 2, on a USB 3 port.

Kind regards,
Ben.


On 17/08/18 14:35, Ben Caradoc-Davies wrote:
> Actually that verification will not work because dd bs is limited to 
> about 2 GiB (signed 32-bit?). The solution is to use "head -c", or 
> because in this case the image size is an exact multiple (502) of 8 MiB, 
> bs=8M count=502. The source confirms that the size argument to head is 
> size_t (64-bit on amd64). This also stops trying to load the whole image 
> into memory.
> 
> Wrong:
> 
> # dd if=/dev/sdb bs=4211081216 count=1 | md5sum
> 0+1 records in
> 0+1 records out
> 2147479552 bytes (2.1 GB, 2.0 GiB) copied, 111.671 s, 19.2 MB/s
> d115d027efbf43eaba4ff2589aab17e8  -
> 
> Right (dd reading a bit more than the image size):
> 
> # dd if=/dev/sdb bs=1G count=4 | head -c 4211081216 | md5sum
> 83a07dc571b7810495f0835e5f390ab8  -
> 
> Right (image size is an exact multiple of 8 MiB):
> 
> # dd if=/dev/sdb bs=8M count=502 | md5sum
> 502+0 records in
> 502+0 records out
> 83a07dc571b7810495f0835e5f390ab8  -
> 4211081216 bytes (4.2 GB, 3.9 GiB) copied, 225.907 s, 18.6 MB/s
> 
> On 17/08/18 11:57, Ben Caradoc-Davies wrote:
>> And if you know the md5sum and exact size size in bytes of the source 
>> image, and have enough memory, you can also verify the write:
>>
>> sudo dd if=/dev/sdX bs=4211081216 count=1 | md5sum
>>
>> $ ls -l osgeolive-12.0beta3-amd64.iso
>> -rw-rw---- 1 ben ben 4211081216 Aug 17 11:40 
>> osgeolive-12.0beta3-amd64.iso
>> $ md5sum osgeolive-12.0beta3-amd64.iso
>> 83a07dc571b7810495f0835e5f390ab8  osgeolive-12.0beta3-amd64.iso
>> $ cat osgeolive-12.0beta3-amd64.iso.md5
>> 83a07dc571b7810495f0835e5f390ab8  osgeolive-12.0beta3-amd64.iso
>>
>> Kind regards,
>> Ben.
>>
>> On 17/08/18 11:09, Ben Caradoc-Davies wrote:
>>> Have you tried writing the raw ISO with dd?:
>>> sudo dd if=osgeolive-12.0beta3-amd64.iso of=/dev/sdX bs=8M; sync
>>
> 

-- 
Ben Caradoc-Davies <ben at transient.nz>
Director
Transient Software Limited <https://transient.nz/>
New Zealand