nasm -D_LOAD_MIN_PARA=0 -D_LOADFULLFAT12=0 -D_FREE_PARA_LIMIT -I ~/proj/lmacros/ ~/proj/ldosboot/boot.asm -D_LOAD_NAME="'LDEBUG'" -o boot12.bin -l boot12.lst

nasm -D_BOOTPATCHFILE="'boot12.bin'" -I ~/proj/msdebug/ -I ~/proj/ldebug/bin/ ~/proj/bootimg/bootimg.asm -I ~/proj/lmacros/ -D_PAYLOADFILE=ldebug.com,lddebugu.com,extlib.eld,testmult.sld -o multi.img && qemu-system-i386 -curses -chardev serial,id=serial2,path=/tmp/vptty-dos -serial null -serial chardev:serial2 -fda multi.img -boot order=a

boot fda
e 0:7C3E "LDDEBUGU"

=== testmult.sld
boot protocol ldos fda/lddebugu.com
e ss:bp-6 as words 400          ; loadseg (say up to below here loaded)
e ss:bp-8 0 0                   ; FAT12 isn't passed
tp FFFFFF while ip < 600        ; go to multi patch area in end2
t 4

~/proj/patchini/patchqry lddebugu.com diskette 1 && mcopy -o -i disktest.img lddebugu.com ::LDDEBUGU.COM