Gee…
They produced more than 100 million DS + DSi consoles more than 75 million 2|3DS consoles (
about 15 scattered in my house – yes I'm mad). It can't be that hard to borrow one to flash ntrboothax onto some cheap, compatible R4.
D*mn! A N3DSXL is such a fine machine, and if the only thing that is wrong with it, is a stupid byte on NAND it is well worth investing some time+money. Those consoles are getting increasingly expensive in good condition. There is no excuse: I literally bricked my test device the same way just to verify that reviving it is easy and fast.
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Please do not start hardmodding. It is so easy to f… up the board beyond repair and ntrboot is all you need.
Did you try contacting nds-card? Maybe something went wrong.