The analysis of Feature Phones (Keitai) has progressed very well in recent months.
The State of Japanese Feature Phone Preservation in 2023
DoCoMo Debug Cable Preservation Info
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And it can be run on an emulator. (videos: Rockman.EXE Legend of Network, Densha de GO...
I went to a garage sell last saturday, and the lady had a PS2 for sale, but she had a sign on it that said "Nintendo -$50", had to laugh, almost bought but she didn't know if worked, and she didn't have controller or cables, so I passed.