The charger in n900 has the job of bringing the battery up high enough so that it can boot. After turning on the CPU, the bootloader takes over charging until it thinks there's enough to start maemo. Maemo takes over charging.

If Maemo fails to boot the process loops indefinitely, with the battery hovering somewhere around the minimal-power-to-boot-maemo threshold.

If the cpu fails at booting then battery will hover at the lower threshold.


In either case it wouldn't be a good battery charger unless it boots completely.