"Dear customers who resell Nintendo 3DS "
"non purchase able 3DS system"
In case if you use equipment which is illegal or unapproved by Nintendo or if you do customization which is unapproved by Nintendo, there is a possibility that Nintendo 3DS become non bootable by system update.
- From Nintendo 3DS terms of agreement
Because of terms of agreement above, Enterking refuses to buy 3DS system with record of illegal or unapproved equipment.
"Request to format before you sell"
To protect from leaking your personal and internet connection information, We ask customer to format system. In case purchasing could not be established after you format 3DS system, Enterking is not responsible for lost datas and settings. Please understand before you format.
Japanese game retailer Enterking issued a notice that it would not be buying back any 3DS units that were used with a R4-type devices - specifically "illegal or unauthorized devices". The notice states that there seems to be a record of such use left on the system. This would be in line with the rumors that the 3DS keeps a log of flash cart use, which then can be checked.
The Nintendo terms of agreement clearly state that it is possible that the 3DS might not be able to boot up after firmware updates if unapproved or illegal devices are used in the 3DS. You've been warned! But will this still stop you?
Here are some videos of flashcards running on Nintendo's new 3DS: