Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've got a Linksys WRT54G and decided to upgrade to the latest firmware to see if it resolves a problem I am having with the router.

But when I read the release notes it says:

Disconnect all wireless clients from the router during the upgrade process. Make sure no wireless clients attempt to associate with the router until the upgrade process is complete.

Problem is, the actual web page of the router itself doesn't mention anything about this. All it says is:

Click on the browse button to select the firmware file to be uploaded to the router.

Click the Upgrade button to begin the upgrade process. Upgrade must not be interrupted.

So now I'm a bit worried. First of all, all the headed machines on my network are connected to the router wirelessly. So, without a lot of extra work I can't disconnect all wireless clients from the router because then I wouldn't be connected to the router and wouldn't be able to perform the upgrade. Second, I'm also a bit concerned because this seems to imply that I need to go around and find every machine that is or might be connected to the router and forcibly go in and turn off WiFi until the upgrade is complete so that no wireless clients will attempt to associate with the router during the upgrade process. Considering that I might not easily have access to some of the machines, this might be problematic as well. (And does this consider people who might be able to see the router, but which aren't even in the building? I'm assuming the security on the router might be disabled during the upgrade as it is telling me to save my settings because they might revert to default settings during the upgrade process.)

So my question is, what does the above statement really mean? What problems might I have if the machine I am trying to upgrade from is on WiFi, or if another machine has WiFi on at the same time? What is really necessary for me to upgrade safely in terms of what is practical for me to do?

share|improve this question
up vote 0 down vote accepted

I've never done that step myself but it sounds reasonable since you don't want to put the router in an unexpected state while updating the firmware. You can disconnect them forcefully by deleting their IP leases using the router's DHCP settings page and disabling the WiFi network (or change its settings so the computers fail when trying to automatically reconnect).

Secondly, you should always update router firmware using a direct, wired connection between the PC and the router. WiFi connectivity is more prone to errors in packet transfer and a corrupted firmware package will potentially brick the router. Do NOT use a WiFi connection to update the firmware.

share|improve this answer
Okay, thanks. I guess I just assumed that since the transfer was over TCP/IP the reliability guarantee would apply, but it sounds like maybe the router isn't saving and verifying the firmware on the device before it uses it. – Michael Feb 10 '13 at 22:00
Even though it is a TCP connection, if the WiFi connection drops during transfer, it can cause the firmware upgrade to fail, and when updating firmware on any device, that can potentially brick the device, since there isn't a way to recover if its firmware code is only partially written. It's like upgrading Windows, and finding some core system files are corrupted, preventing it from booting. Except there isn't a way to restore a backup because the code that does the install is in the OS, which is broken. – Ben Richards Feb 10 '13 at 22:05

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .