It looks like the latest firmware is bricking systems modded or not.
Wii Update 4.2 Is Killing Wiis Dead - Wii - Kotaku
Some of you have reported problems with your Wii console after updating to the Wii System Menu 4.2. The symptoms most people are describing usually occur when the Wii has been modified. However, some of you also mention your system has never been modified.
We'd like to help get your system working properly again. If you're experiencing problems with your Wii console after downloading Wii System Menu 4.2, and you believe your system has not been modified, please give us a call. If we find that you have a normal system and the update caused your system to not work, we'll repair it at no charge.
Please call our Customer Service Department at your earliest convenience, 1-800-255-3700. We are open 6 AM to 7 PM, Pacific Time, 7 days a wee