Good day everyone

after a few days trying, I'm asking your help Pleaase

I'm actually waiting for my arduinoboy from catskull (who's shop is super nice )

and I'll use it and mGB with an old electric organ (not analog but with chips inside)

I cannot change the midi channels on the organ itself

first of all I don't want to use arduinoboy maxpat to acheive those midi changes because I'd like to have as many different roms needed on my nonfinite : bennvenn's gb/sd cart... i don't need a laptop each time I  change my config.

So I wanted to modify mGB roms in order to arrange the midi chans to my convenience.
like poly on 3rd channel and nothing else or wav on 2nd chan or (lets try the impossible)pu1 and pu2 on the same chann and wav elsevere.

to do that I've dug into mGBASMMidiFunctions.s and found the midi channels relating lines.

that was the easy part for me

but then I tryed to Make the rom and then I got lost.

tryed to use the make_mGB.bat , got folder issues ,messed with folders, downloaded gbdk insted of using gbdk-n from trash's github...... missing mGB.o.......

So If you think my project is doable with a little help, then it will be rally apreciated

Tell me if I'm dumb

I havent tryed to modify the rom directly with bgb

got a linux laptop and can use windows if needed

I'm gonna stop this post now
thanks for reading and stuff
If you need more details I'll do my best


and don't forget that's nanoloop sh.t

Last edited by Analylogiq (Jan 10, 2018 6:46 pm)


I built it a few years ago and don't remember having any issues at all. On mac os. I did use the makefile though. Go into the source folder and make build and it should work, assuming gbdk-n is in the right place and everything.


you put me on the good way

Now sdcc is missing so I'm installing the package



sdcc installed make script getting closer.......but

at 1: error 4: 'fopen' failed on file 'mgb.c'

and there I'll stop for today

there's a Raphael on sourceforge  who seems to know lots about sdcc and fopen
la suite au prochain épisode


okay it was mgb in the makefile and mGB in the files..... damm

now I'm looking for gb.lib

If I succeed I'll post the roms....

Last edited by Analylogiq (Jan 12, 2018 6:23 am)


?ASlink-Error-<cannot open> : "/home/zavous/EMS/mgb/mGB-master/gbdk-n/bin/../lib/crt0.rel"
Makefile:7 : la recette pour la cible « build » a échouée
make: *** [build] Erreur 1

getting further and crazy lol


well I took the problem from the beginning
and I had forgotten to make gbdk-n ....

now Isucceeded making the rom
have to test it btw

hope these posts can help another noob (dumb) like me


I tested the mGB midi modded roms and it worked as expected with the nanoloopusbmidi...

cannot wait the postman with Catskull's package

here are the roms I did
one has got poly only on midichannel 2
an other on ch 3
one Pu1 Nothing Wave Noiz on ch 1, 3, 4
one in only Wav on ch1
and one Poly Wav Noiz Pu1 Pu2  on ch 1,2,3,4,5

links in disorder.. … sp=sharing … sp=sharing … sp=sharing … sp=sharing … sp=sharing



I'm trying to do something similar, I want to change the MIDI CC numbers.
I have done that in the mGBASMMidiFunctions.s file, but I have problems with compiling.

This is the message I get:

mgb.c:2:17: fatal error: mGB.h: No such file or directory
compilation terminated.
make: *** [build] Error 1

I have downloaded gbdk-n, and just put it in the folder with that name in the mGB-master folder.
I have installed SDCC and MSYS 1.0.11 with Make 3.81

Any suggestions?

Cheers, Hal