via Aldostools forum post
.If you use webMAN MOD, the easier method to swap discs is this:
1- Mount the CUE/BIN of one the multi disc PS1 game (e.g. disc 1)
2- Start the game and play until the point it asks to swap the disc (e.g. disc 2).
3- Use a tablet, laptop or smartphone to mount the disc 2 from Chrome, Safari or any Internet browser:
http://IP-address-of-your-PS3/mount_ps3/dev_hdd0/PSXISO/name_of_game_disc_2.BIN
Replace the URL with the correct IP address and path of the 2nd disc.
/mount_ps3 is used instead of
/mount.ps3 to skip the warning and force the game to be mounted.