Pressure bleed is the way to bleed anymore.. if you went in with no pedal and bled in attempt to flush and get pedal, resulting in no pedal still.. likely into an ABS module..
Once in a great while we see them start to by-pass internally, result is poor to no pedal.
Old HI-SCAN and current GDS have ability to go in and run pump. You going to have to visit dealer for that, then while plugged in, run the ECU UPGRADE mode and update the PCM to latest software (there is a warm ambient cold start/stumble update a lot not have yet, maybe a trans update too, but they'll know when they read ROM and see waht GDS offers up.
XD Elantra might be different from 1997 Pontiac Bonneville, but...
we had to change all brake lines (rear passenger rusted through). Since all of them were in similar condition, all got to be replaced.
As you may assume that caused all brake fluid to be drained.
After all was done, refill the reservoir, start pumping the pedal - all four wheels bled on stand still. A lot of fluid was pumped out.
Every wheel was repeated two times (after the whole cycle).
As a result, master, ABS, and all wheels were bled. Pedal is hard (as it should be), no pumping will change its position, and ABS works OK.
To make sure it was done OK - ABS was activated. Simply by slamming the brakes on gravel road at 35 MPH. Enough time for ABS to cycle several times. One more bleeding and call it a day.
No visit to dealer, not costly repairs... but again, it was not Hyundai.
I would suggest try regular bleeding. Pump it a few times and have the other person to bleed - but a quick opening the bleed valve. Not slowly releasing fluid, but full turn to let the fluid flow at max velocity.
One note - for whatever reason, which did not make any sense to me as the sections are separate, when rear was bled and seemed to be OK, but front has not been finished yet, the pedal was still soft. It would brake at all. We learned hard way... One would assume - at least one section is OK, right? Nope...