iPad 1 endless reboot loop with no iTunes reformat
I solved my problem by replacing the battery. Apparently, the old one was so dead it wasn't even capable to boot up the system. Once it was replaced, I was able to access the DFU mode then reinstall the OS. This is the only solution available throughout the Internet. I even spoke with an Apple assistant, and he recommended me to not bother with this old piece of... plastic! ;)