In some Swedish dialects "rd" is pronounced as a thick "l", so you get things like:

gård - gål

vard - val

jord - jol

The "G" before "ä" would be soft, so it could be spelled "Gä-" or "Gjä-" or "Giä-", or even "Jä-".

So Giälsbol is just a variant spelling of Gärdsbol.

// Bo Johansson