If your device has an SD card slot, get yourself a 4GB card or larger. Then the next thing you must do is upgrade your bootloader using the old card (2GB or smaller) BEFORE trying to use a larger card 4GB+. Here's how:
Bootloader 5.5136 for all ONE models only
If your device does not have an SD card slot, then you are limited to the internal memory, which could be 2GB or even 1GB. In this case, you can only use the smaller, zoned Europe maps which may have less coverage.
Next, I suggest you install the 9.170 SE navcore to be able to use almost any map you want which includes the features IQ/ALG. I use the same navcore on my TomTom ONE:
Navcores 9.061 & 9.170 for 32Mb ONE models [by mark cat]
If your device has a card slot, then the map you need is Europe_905_4754:
To install the above, follow the clean install tutorial, leaving out steps 4 & 5, and instead copy across the 9.170 SE navcore folders and files directly onto the root of the SD card. Then continue with the rest of the tutorial:
TUTORIAL: Clean Install - How to install the latest map and navcore from scratch!