I want to install priiloader , but I really don't know how . my wii system firmware is 4.1J and in every post it said priiloader for 4.1E and 4.1U. Can I use one of those or I need different one? and it said that "IT IS HIGHLY RECOMMENDED TO INSTALL PRIILOADER ONLY ON A WII WITH UNMODIFIED IOSs!". But my wii has ios 249 cios 20. Is it safe to install priiloader???
yes, safe, go for it. better choice would be to actually follow our softmod guides from beginning to end.
go for the any wii guide for example, link below. everything explained in detail.