Wireless Firmware Updating

By Steven J. Vaughan-Nichols

April 01, 2003

Be very careful... Updating firmware always sounds like a good idea, and can mean substantial boosts in performance and stability --but it can also be the road to WLAN ruin.

Upgrading firmware sounds like a good idea. At the least, you should gain greater stability with your wireless devices, at best, you may actually see a substantial performance boost. What's not to like? Well, a lot actually.

You see, short of opening up the case and poking around with your fingers while a device is still on, upgrading firmware is about as dangerous an operation as you can do with electronic hardware.

That's because firmware is the embedded software that actually stands between you and the hardware. Make a mistake updating a simple software program on your computer, and if worse comes to worse, you just reinstall the program. Make a mistake updating firmware and your $500 access point/bridge becomes a rather ugly paperweight.

Curiously enough, when you had to physically replace your older equipment's Read Only Memory (ROM) firmware chips with new and improved ones, upgrading was actually a bit easier. This presumes, of course, that you can handle a chip remover tool and take basic precautions against static. Today, while some firmware is still locked away in ROM chips, most of Wi-Fi firmware is kept in programmable read-only memory (PROM) , which can be updated using software. It sounds easier, but in practice, it's all too easy to make mistakes.

In Wi-Fi, PROMs are almost always one of two technologies: electrically erasable programmable read-only memory (EEPROM) or Flash Memory (sometimes called Flash EEPROM) . The practical difference is that EEPROM can only be updated one byte at a time whereas Flash Memory can be updated in blocks. The net effect is to make Flash a bit faster than EEPROM. For most users, however, it's a difference that makes no difference. You take what the vendor gives you and don't worry about it since from your viewpoint the updating methods look and act the same.

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