I had the same issue, I though my 4400 fried out so i bought another used one on Ebay. Few months later i ran into the bootloop issue and was contemplating of buying a Sony HU instead. Today December 13 2023 i ran into this forum by HondaR, Followed the instruction and my unit is back online. Thank you so much HondaR for this help. Just follow the instructions and you will have your system back on.
https://mega.nz/file/SdJCgKCJ#13zrFlogMCWNohCvuFsDFcC1uniHgufVZJxZlQPHUag
https://sourceforge.net/projects/win32diskimager/
