QEMU, No bootable device, Windows Subsystem for Linux
<p>I'm learning how to build a basic OS kernel with <a href="https://intermezzos.github.io" rel="nofollow">https://intermezzos.github.io</a></p>

<p>I've create my <code>.iso</code> file and I'm at the point where I am runnning <code>qemu-system-x86_64 -cdrom os.iso</code>
When I press enter, QEMU runs a window with the following output: </p>

<pre><code>Booting from Floppy...
Boot failed: could not read the boot disk

Booting from DVD/CD...
Boot failed: Could not read from CDROM (code 0004)
Booting from ROM...
iPXE (PCI 00:03.0) starting execution...ok
iPXE initializing devices...ok

iPXE 1.0.0+git-20131111.c3d1e78-2ubuntu1.1 -- Open Source Network Boot Firmware
-- http://ipxe.org
Features: HTTP HTTPS iSCSI DNS TFTP AoE bzImage ELF MBOOT PXE Menu

net0: 52:54:00:12:34:56 using 82549em on PCI00:03.0 (open)
  [Link:up, TX:0 TXE:0 RX:0 RXE:01]
Configuring (net0 52:54:00:12:34:56)...ok
net0: 10.0.2.15/255.255.255.0 gw 10.0.2.2
Nothing to boot: No such file for directory (http://ipxe.org/2d03e13b)
No more network devices

No bootable device.
</code></pre>

<p>I went to the website listed in the output (<a href="http://ipxe.org/2d03e13b" rel="nofollow">http://ipxe.org/2d03e13b</a>) and one of the tips is that I might <code>Use the iPXE command line to perform DHCP manually</code>, however when I press <code>CTRL + B</code> to access cli, I'm not able to do so.</p>

<p>Where do I look next to troubleshoot this problem of not being able to boot my <code>.iso</code>?<br>
How do I make QEMU have access to keyboard input?</p>

<hr>

<p><strong>UPDATE</strong><br>
I don't know how, but I'm am now able to use <code>CTRL + B</code> to access iPXE command line.</p>

<p>This seems like a good place to start diagnosing my problem of not being able to boot my <code>.iso</code>.</p>

<p>What am I looking for?</p>

<hr>

<p><strong>UPDATE 2</strong><br>
Thanks to Peter Maydell's suggestion below, I've tested a known-good <code>iso</code> image (<a href="https://alpinelinux.org/" rel="nofollow">https://alpinelinux.org/</a>), running <code>qemu-system-x86_64 -cdrom alpine-3.4.3-x86_64.iso</code> and it booted perfectly just as I expected.</p>

<p>I've rewritten my files from <a href="https://intermezzos.github.io" rel="nofollow">https://intermezzos.github.io</a> to create a new <code>iso</code> image, this time copy and pasting the code from the repository, just in case I was previously inputting typos.</p>

<p>Still not booting. On to the next clue... </p>