R4i is slot-1 booter + SDHC socket . www.Best4DS.com said it works on DSL . I bought 5 R4i , but it wont work . They emailed me a long list of instructions how to troubleshoot the R4i firmware . I told them i would not fix their buggy code . Earlier i got R4 from dragonDS.com . With Moonshell installed on 4GB SDHC cards . Works well . There were no problems with www.dragonDS.com
there are loads of versions of R4 (possibly R4i buy now is the cartridge an R4 repackaged as an R4i i'd ask myself)try the micro sd card out of the working one in the non-working one, if the card loads you just had the wrong firmware on the micro sd card and can back the good micro sd card up to pc, then copy all the files to the micro sd card that wont boot. is the card a genuine or fake?
that is strange is he selling his personal stuff via a company, then instead of someone else receiving the faulty goods back instead of him, tot make sure he gets it back he gives you his address