As I know it is possible to boot up some bootable images (like Linux, Clonezilla, management applications and others) over a PXE (Preboot Execution Environment) server with an Ethernet device (802.3).
Can the same thing be done with an Ethernet WiFi (802.11) device? I tested with my notebook but my BIOS appears to not enable booting from WiFi devices. Is it possible with some specific WiFi cards and/or a specific BIOS?
At least one vendor has solved netbooting over Wi-Fi, but you're not likely to be able to do with with mix-and-match motherboards and Wi-Fi adaptors at this time.
You can boot MacBook Airs via Wi-Fi, as long as another machine on the network is sharing a Mac OS X install DVD via Mac OS X's DVD sharing feature. Since MBA's don't necessarily come with an optical drive or Ethernet adaptor, this can be the only way for some users to do a clean OS install.
Apple has built drivers for those Wi-Fi chipsets, as well as a UI for joining a Wi-Fi network, into the EFI bootROM on those models. As far as I know this is an Apple proprietary scheme, not PXE-based.
If your WLAN adapter doesn't support PXE, then no, you can't do PXE over wireless.
If your laptop has an Ethernet adapter, however, you can connect it to a wireless access point that can function as a bridge (or a dedicated wireless bridge). I've tried it myself, but it was too slow, I'd rather just move the laptop near an Ethernet switch/router.
iPXE has development support for ath5k, and apparently now ath9k wireless chips, and I'm assuming also the 818x RALINK chips that gPXE was developing.
Note that you'll be doing a lot of compiling and there won't be any handy guides to help you.
Note also that you won't be able to burn a PXE image onto a wireless card itself, but you should be able to do so with a wired LAN or a motherboard.
Also note - this doesn't apply to USB.
It's hard to get a handle on where to start, but you should probably download the source from ipxe.org, and try https://www.google.com.au/search?q=site%3Aipxe.org+ath5k
It looks like the guys over at Etherboot have provisional support for booting off a Wifi card. only a couple of cards supported, but you may be lucky...
Google for "iPXE". they claim to have support for booting off of a wireless network and even a web address. Also you might be able to flash their ROM over your wireless card's ROM instead of booting from the test iso you can download
As per my experience, I have some computers having a wireless antenna. They had a very small ssd hard disk of 512M. I installed on that small hard disk iPXE. Unfortunately the specific computers may not boot normally via pxe ( neither via external storage for security reasons).
So at boot the iPXE console appears. So I am able by hand to get an ip for the wired or wireless adapter. I am also able via commands to download an initrd.img and vmlinuz images and boot. Probably iPXE uses bios calls that allow for that ( it may not be true on an other platform). The image that I loaded was from an ltsp server. I you arrive to that point you may also load any remote image as e.g. The problem afterwards was that the kernel loaded hadn't the drivers for the specific card. So I had to add them to the initrd and do some mangling in order to finaly be able to arrive to the final connection. So yes under conditions wireless PXE boot works if the mother boards supports it. So I was finally able to have a complete wireless LTSP client.
2024 update
PXE is much more prevalent today. Wikipedia says for Preboot eXecution Environment (PXE):
PXE acceptance since v2.1 has been ubiquitous; today it is virtually impossible to find a network card without PXE firmware on it. The availability of inexpensive Gigabit Ethernet hardware (NICs, switches, routers, etc.) has made PXE the fastest method available for installing an operating system on a client when competing against the classic CD, DVD, and USB flash drive alternatives.
Using PXE requires several components.
The first is a PXE server which also does DHCP and TFTP. An example of the required setup can be found in the Red Hat article How to set up PXE boot for UEFI hardware.
Almost all NIC firmwares can today do almost all the steps involved in the PXE boot process, starting from the DHCP request, assign network parameters such as IP and subnet mask, contacting the PXE boot server (TFTP server) and receive the PXE image.
However, the process still needs to initiated by the BIOS/UEFI firmware, which also needs to cooperate with the NIC in storing the PXE in RAM and executing it.
Most BIOS/UEFI firmware today are supposed to support this possibility. But if this capability is required, it's better to verify its existence in the BIOS and its compatibility with the chosen NIC. It's safer when buying a ready-made computer.
For example, an HP Technical White Paper from November 2023 describes Preboot Wireless Networking on HP Business PCs describes some limitation on the firmware:
On Intel systems, use of AMT Wi-Fi and pre-boot Wi-Fi are mutually exclusive; only one can be enabled at one time. Intel systems have AMT enabled by default, so to use pre-boot Wi-Fi AMT must be disabled first.
For AMD systems, use of DASH (Desktop and mobile Architecture for System Hardware) and pre-boot Wi-Fi are mutually exclusive; only one can be enabled at one time. AMD systems have pre-boot Wi-Fi enabled by
Fast Boot needs to be disabled to use pre-boot Wi-Fi. IPV4 and IPV6 boot entries will have ‘Wi-Fi’ string appended to those entries to differentiate between wired and Wi-Fi boot entries. default, so to use DASH pre-boot Wi-Fi must be disabled first.
This is the way that this works on suitable HP computers :
to configure preboot Wi-Fi thru BIOS setup which is accessible during system bootup by using the ‘F3’ function key. On entering F3 menu, ‘Wi-Fi Configuration’ link will provide a link to MAC address of Wi-Fi controller which in turn provides the connection status, list of access points and allow users to connect to it by entering credentials for various types of Wi-Fi topology. File explorer will be available to select the certificate files from media and unique GUID value is required for each certificate since it’s stored as part of same variable.
The PXE process will include these steps :
On entering F3 menu, ‘Wi-Fi Configuration’ link will provide a link to MAC address of Wi-Fi controller which in turn provides the connection status, list of access points and allow users to connect to it by entering credentials for various types of Wi-Fi topology. File explorer will be available to select the certificate files from media and unique GUID value is required for each certificate since it’s stored as part of same variable.
Below is the first boot selection screen that one will see on HP supporting computers when pressing the F3 key at the start of the boot:
There are some wireless network cards that recieve power even in an "off" state which can use "Wake-on-WLAN" but as for PXE boot over wireless I think, while interesting, would be a) very slow (compared to ethernet) and b) only preferable for very small distro enviroments.
I would say that, no, you cannot 'technically' PXE boot from wireless with consumer-class equipment because the wireless has not been loaded at the time PXE loads. 2 options I can think of:
My guess is that for 10-12 users the wifi should be ok.
If you needed more then you'd need to setup separate access points using different channels/frequencies.
Industry testing has shown that enterprise 802.11n APs can achieve 150+ Mbps aggregate throughput under real world test conditions (see Cisco/Intel test and Network World test). However, it is not uncommon for 15 or more users to associate with the same AP. Therefore the average throughput per user will vary as the number of users per AP varies.
So a wireless N boot given some forethought and understanding of limits of users etc. should at least equal or beat 10Mbps ethernet up until the number of users sharing the wifi access point are enough to reduce throughput, increase latency etc.
It's possible.
Download the image from ipxe iso and make bootable usb disk with dd if=ipxe.iso of=<usb device path> and boot it.
Instructions to follow on gPXE wireless
ipxe is successor of gPXE.
If this is for service purposes then one workaround could be to use iPXE and it's support for using iPhone or Android Tethering.
One thing to note here tho is that the phone will be the DHCP server, so additional iPXE scripting is needed to connect and download files from sever/internet.
