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I had to move some files around, but i think i have it working. Thank you so much for all of yalls help! Yall are the best!!!!

i would review the stepper motor docs and make sure your timings match what the drives are looking for, this may help resolve your drive side following error, the timings are usually listed in a graph showing the uSec for step and dir and would be entered in the configuration file, yours seem quite big to me from what i am used too seeing.

the first thing I would be looking at is resolving the drive errors to ensure that what linuxcnc is commanding is actually being executed by the drive without faults, otherwise is doesn't matter what linuxcnc is sending. verify your stepper timings are set correctly, then try resetting the config to the basic stepper settings without any "fixes". test and ensure no drive faults and get another test cut measurement, once you have no drive faults you can begin troubleshooting the linuxcnc side of things. I would set any scaling to preliminary settings for the motion components advertised ratios such as lead and transmission reductions for pulleys. remove any fixes here from the equation so you have a good base point to start from. I have found that any deviations here will be very very small and certainly not in the realm of tenths of a mm. also remove any backlash compensation. you really want to run your test cuts without anything except the very base setting requirements to ensure something you did while running with drive faults isn't skewing your results.

other things to verify.  drive settings for microstepping, ensure these are correctly set and not beyond what the drive can handle at 200khz step frequency and linuxcnc output.  sometimes setting these a little more conservatively is better.

I also just saw in your ini config you shared that your step scale is different for x and y axis, but you state you are running the same screws and 2:1 reduction, the step scale here should be the same provided the drive microstepping settings are the same for both axis (and they should be)  both should be set to the systems axis setting test with the least granular microstepping setting for continuity.

I omitted that file and the GUI launched but with a new error.. LOL This thing is driving me crazy.

Traceback (most recent call last):
File "/usr/bin/probe_basic", line 8, in <module>
sys.exit(main())
~~~~^^
File "/usr/lib/python3/dist-packages/probe_basic/__init__.py", line 20, in main
qtpyvcp.run_vcp(opts, VCP_CONFIG_FILE)
~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/qtpyvcp/__init__.py", line 26, in run_vcp
run(*args, **kwargs)
~~~^^^^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/qtpyvcp/app/__init__.py", line 129, in run
launch_application(opts, config)
~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
File "/usr/lib/python3/dist-packages/qtpyvcp/app/launcher.py", line 93, in launch_application
raise IOError('The specified POSTGUI_HALFILE does not exist: %s' %
postgui_halfile)
OSError: The specified POSTGUI_HALFILE does not exist: /home/kris/linuxcnc/configs/my_mill/probe_basic_postgui.hal

RotarySMP wrote:

Hi Tom,

Who me ?

I'm sure I messed something up again.. here's a copy of my HAL& INI files

HAL
# This file was created with the Mesa Configuration Tool on Nov 21 2025 06:35:29
# If you make changes to this file DO NOT run the configuration tool again!
# This file will be replaced with a new file if you do!

# kinematics
loadrt [KINS](KINEMATICS)

# motion controller
loadrt [EMCMOT]EMCMOT servo_period_nsec=[EMCMOT]SERVO_PERIOD num_joints=[KINS]JOINTS num_dio=6 num_aio=3

# hostmot2 driver
loadrt hostmot2
loadrt [HM2](DRIVER) board_ip=[HM2](ADDRESS) config="sserial_port_0=00000000"

setp hm2_[MESA](BOARD).0.watchdog.timeout_ns 10000000

loadrt pid names=pid.x,pid.y,pid.z

# THREADS
addf hm2_[MESA](BOARD).0.read servo-thread
addf motion-command-handler servo-thread
addf motion-controller servo-thread
addf pid.x.do-pid-calcs servo-thread
addf pid.y.do-pid-calcs servo-thread
addf pid.z.do-pid-calcs servo-thread
addf hm2_[MESA](BOARD).0.write servo-thread

# amp enable
net motion-enable <= motion.motion-enabled

# Global PWM setup
setp hm2_[MESA](BOARD).0.pwmgen.pwm_frequency 75000

# Board: 7i97t

# Axis: X Joint: 0 Output: 0
# PID Setup
setp pid.x.Pgain [JOINT_0](P)
setp pid.x.Igain [JOINT_0](I)
setp pid.x.Dgain [JOINT_0](D)
setp pid.x.bias [JOINT_0](BIAS)
setp pid.x.FF0 [JOINT_0](FF0)
setp pid.x.FF1 [JOINT_0](FF1)
setp pid.x.FF2 [JOINT_0](FF2)
setp pid.x.deadband [JOINT_0](DEADBAND)
setp pid.x.maxoutput [JOINT_0](MAX_OUTPUT)
setp pid.x.error-previous-target True

# joint-0 enable chain
net joint-0-index-enable <=> pid.x.index-enable
net joint-0-index-enable <=> joint.0.index-enable
net joint-0-index-enable <=> hm2_[MESA](BOARD).0.encoder.00.index-enable

net joint-0-enable <= joint.0.amp-enable-out
net joint-0-enable => pid.x.enable
net joint-0-enable => hm2_[MESA](BOARD).0.pwmgen.00.enable

# PWM Generator setup
setp hm2_[MESA](BOARD).0.pwmgen.00.dither true
setp hm2_[MESA](BOARD).0.pwmgen.00.output-type 1 #PWM pin0
setp hm2_[MESA](BOARD).0.pwmgen.00.offset-mode 1 # offset mode so 50% = 0
setp hm2_[MESA](BOARD).0.pwmgen.00.scale [JOINT_0]SCALE

# ---Encoder feedback signals/setup---
setp hm2_[MESA](BOARD).0.encoder.00.counter-mode 0
setp hm2_[MESA](BOARD).0.encoder.00.filter 1
setp hm2_[MESA](BOARD).0.encoder.00.index-invert 0
setp hm2_[MESA](BOARD).0.encoder.00.index-mask 0
setp hm2_[MESA](BOARD).0.encoder.00.index-mask-invert 0
setp hm2_[MESA](BOARD).0.encoder.00.scale [JOINT_0]ENCODER_SCALE

# position command and feedback
net joint-0-pos-cmd <= joint.0.motor-pos-cmd
net joint-0-pos-cmd => pid.x.command

net joint-0-pos-fb <= hm2_[MESA](BOARD).0.encoder.00.position
net joint-0-pos-fb => joint.0.motor-pos-fb
net joint-0-pos-fb => pid.x.feedback

# PID Output
net joint.0.output <= pid.x.output
net joint.0.output => hm2_[MESA](BOARD).0.pwmgen.00.value

# Encoder Setup
setp hm2_[MESA](BOARD).0.encoder.00.scale [JOINT_0](ENCODER_SCALE)
setp hm2_[MESA](BOARD).0.encoder.00.counter-mode 0
setp hm2_[MESA](BOARD).0.encoder.00.filter 1
setp hm2_[MESA](BOARD).0.encoder.00.index-invert 0
setp hm2_[MESA](BOARD).0.encoder.00.index-mask 0

INI
# This file was updated with the Mesa Configuration Tool on Nov 21 2025 06:35:29
# Changes to most things are ok and will be read by the Configuration Tool

[MESA]
VERSION = 2.1.8
BOARD = 7i97
BOARD_NAME = 7i97t
FIRMWARE =
CARD_0 = None
CARD_1 = None

[EMC]
VERSION = 1.1
MACHINE = my mill
DEBUG = 0x00000000

[HM2]
DRIVER = hm2_eth
ADDRESS = 10.10.10.10

[DISPLAY]
DISPLAY = probe_basic
OPEN_FILE = ~/linuxcnc/nc_files/pb_examples/blank.ngc
CONFIRM_EXIT = False
LOG_FILE = sim.log
LOG_LEVEL = DEBUG
PREFERENCE_FILE = sim.pref
CONFIG_FILE = custom_config.yml
POSITION = 0x0
PROGRAM_PREFIX = /home/kris/linuxcnc/nc_files
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
MAX_FEED_OVERRIDE = 2.000000
MAX_SPINDLE_OVERRIDE = 2.000000
MIN_SPINDLE_OVERRIDE = 0.500000
DEFAULT_SPINDLE_SPEED = 300
MIN_LINEAR_VELOCITY = 0.016670
DEFAULT_LINEAR_VELOCITY = 10.00000
MAX_LINEAR_VELOCITY = 10.000000
DEFAULT_ANGULAR_VELOCITY = 36.000000
MAX_ANGULAR_VELOCITY = 360.000000
MIN_ANGULAR_VELOCITY = 1.666667
PROGRAM_PREFIX = ~/linuxcnc/nc_files
INCREMENTS = JOG .01in .001in .0001in
GEOMETRY = xyzac
USER_TABS_PATH = user_tabs/
USER_BUTTONS_PATH = user_buttons/
USER_DROS_PATH = user_dro_display/
DRO_DISPLAY = XYZ
OFFSET_COLUMNS = XYZR
TOOL_TABLE_COLUMNS = TZDR
KEYBOARD_JOG = true
KEYBOARD_JOG_SAFETY_OFF = true
ATC_TAB_DISPLAY = 0
USER_ATC_BUTTONS_PATH = user_atc_buttons/

CYCLE_TIME = 0.1
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 1
OPEN_FILE = ""

[KINS]
KINEMATICS = trivkins coordinates=XYZ
JOINTS = 3

[EMCIO]
EMCIO = iov2
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl

[RS274NGC]
RS274NGC_STARTUP_CODE = F10 S300 G20 G17 G40 G49 G54 G64 P.001 G80 G90 G91.1 G92.1 G94 G97 G98
PARAMETER_FILE = probe_basic.var
OWORD_NARGS = 1
NO_DOWNCASE_OWORD = 1
SUBROUTINE_PATH = subroutines

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
SERVO_PERIOD = 2000000

[TASK]
TASK = milltask
CYCLE_TIME = 0.010

[TRAJ]
AXES = 3
COORDINATES = X Y Z
LINEAR_UNITS = inch
ANGULAR_UNITS = degree
MAX_LINEAR_VELOCITY = 3.4
NO_FORCE_HOMING = 1

[HAL]
HALUI = halui
POSTGUI_HALFILE = probe_basic_postgui.hal
TWOPASS = on
HALFILE = main.hal
HALFILE = io.hal

[AXIS_X]
MIN_LIMIT = -14
MAX_LIMIT = 14
MAX_VELOCITY = 10
MAX_ACCELERATION = 10

[JOINT_0]
CARD = 0
TAB = 0
AXIS = X
MIN_LIMIT = -14
MAX_LIMIT = 14
MAX_VELOCITY = 10
MAX_ACCELERATION = 10
TYPE = LINEAR
SCALE = 4
ANALOG_SCALE_MAX = 10
ANALOG_MIN_LIMIT = -10
ANALOG_MAX_LIMIT = 10
ENCODER_SCALE = -40000
FERROR = 25
MIN_FERROR = 25
DEADBAND = 0
P = 10
I = 0
D = 0
FF0 = 0
FF1 = 1
FF2 = 0
BIAS = 0
MAX_OUTPUT = 100
MAX_ERROR = 25
HOME = 0
HOME_OFFSET = -14
HOME_SEARCH_VEL = -1
HOME_LATCH_VEL = 1
HOME_FINAL_VEL = 0
HOME_USE_INDEX = True
HOME_IGNORE_LIMITS = True
HOME_IS_SHARED = True

[AXIS_Y]
MIN_LIMIT = -9
MAX_LIMIT = 9
MAX_VELOCITY = 10
MAX_ACCELERATION = 10

[JOINT_1]
CARD = 0
TAB = 1
AXIS = Y
MIN_LIMIT = -9
MAX_LIMIT = 9
MAX_VELOCITY = 10
MAX_ACCELERATION = 10
TYPE = LINEAR
SCALE = 4
ANALOG_SCALE_MAX = 10
ANALOG_MIN_LIMIT = -10
ANALOG_MAX_LIMIT = 10
ENCODER_SCALE = -40000
FERROR = 25
MIN_FERROR = 25
DEADBAND = 0
P = 10
I = 0
D = 0
FF0 = 0
FF1 = 1
FF2 = 0
BIAS = 0
MAX_OUTPUT = 100
MAX_ERROR = 25
HOME = 0
HOME_OFFSET = -9
HOME_SEARCH_VEL = -1
HOME_LATCH_VEL = 1
HOME_FINAL_VEL = 0
HOME_USE_INDEX = True
HOME_IGNORE_LIMITS = True
HOME_IS_SHARED = True

[AXIS_Z]
MIN_LIMIT = -17
MAX_LIMIT = 0
MAX_VELOCITY = 5
MAX_ACCELERATION = 5

[JOINT_2]
CARD = 0
TAB = 2
AXIS = Z
MIN_LIMIT = -17
MAX_LIMIT = 0
MAX_VELOCITY = 5
MAX_ACCELERATION = 5
TYPE = LINEAR
SCALE = 4
ANALOG_SCALE_MAX = 10
ANALOG_MIN_LIMIT = -10
ANALOG_MAX_LIMIT = 10
ENCODER_SCALE = 40000
FERROR = 25
MIN_FERROR = 25
DEADBAND = 0
P = 10
I = 0
D = 0
FF0 = 0
FF1 = 1
FF2 = 0
BIAS = 0
MAX_OUTPUT = 100
MAX_ERROR = 25
HOME = -1
HOME_OFFSET = 0
HOME_SEARCH_VEL = 1
HOME_LATCH_VEL = 1
HOME_FINAL_VEL = 0
HOME_USE_INDEX = True
HOME_IGNORE_LIMITS = True
HOME_IS_SHARED = True

[INPUTS]
# DO NOT change the inputs they are used by the configuration tool
INPUT_0_8 = Joint 0 Plus Minus Home
INPUT_INVERT_0_8 = True
INPUT_SLOW_0_8 = False
INPUT_0_9 = Joint 1 Minus Home
INPUT_INVERT_0_9 = True
INPUT_SLOW_0_9 = False
INPUT_0_10 = Joint 1 Plus
INPUT_INVERT_0_10 = True
INPUT_SLOW_0_10 = False
INPUT_0_11 = Joint 2 Plus Home
INPUT_INVERT_0_11 = True
INPUT_SLOW_0_11 = False
INPUT_0_12 = Joint 2 Minus
INPUT_INVERT_0_12 = True
INPUT_SLOW_0_12 = False
INPUT_0_14 = Lube Level
INPUT_INVERT_0_14 = False
INPUT_SLOW_0_14 = False

[OUTPUTS]
# DO NOT change the outputs they are used by the configuration tool
OUTPUT_0_0 = Spindle CW
OUTPUT_INVERT_0_0 = False
OUTPUT_0_1 = Spindle CCW
OUTPUT_INVERT_0_1 = False
OUTPUT_0_2 = Coolant Flood
OUTPUT_INVERT_0_2 = False
OUTPUT_0_3 = Lube Pump
OUTPUT_INVERT_0_3 = False

[OPTIONS]
# DO NOT change the options they are used by the configuration tool
LOAD_CONFIG = True
INTRO_GRAPHIC = emc2.gif
INTRO_GRAPHIC_TIME = 0
MANUAL_TOOL_CHANGE = True
CUSTOM_HAL = False
POST_GUI_HAL = False
SHUTDOWN_HAL = False
HALUI = False
PYVCP = False
GLADEVCP = False
LADDER = False
BACKUP = True

Did you eventually manage to get the NVIDIA rendering to work?

Ubuntu and GhostBSD (and probably others as well) install the proprietary NVIDIA driver (not the latest version, generally 535, or 470 if the GPU does not support driver version 535) for supported NVIDIA GPUs by default when you install the OS, which should really be the case for all Linux distros.

Windows also installs the proprietary NVIDIA driver automatically, if your GPU is at all supported. However, it installs a really old version (450, I think), even if your GPU supports the latest driver, which is stupid.

You could try running:
sudo apt update
sudo apt install nvidia-driver-full
sudo reboot

WARNING: THIS MAY BREAK YOUR SYSTEM
Consider making a backup of your system first, or asking for advice regarding the nvidia-driver package and the preempt_rt kernel and just Debian in general.
If you have an unused HDD or SSD, consider taking out your working setup's drive and putting in the empty one, then installing the LinuxCNC 2.9.4 ISO to that, and then trying out those commands to install the "real" NVIDIA drivers, so you won't risk breaking your working install and setup.

The ini file is pointing to an io.hal file that does not exist in that folder.
You can try omitting that entry in the ini file, but might be needed for the config to work, so better try to find the file if you are sure it is needed.

twopass:CANNOT FIND FILE FOR:io.hal

seems that you are telling it to load 'io.hal' somewhere but don't have that file in your config.

So i was able to get PB to launch and then i tried to do the modifications that were recomended on the start screen. I modified my HAL and INI files and now have the following error report..
Error report created by /usr/lib/tcltk/linuxcnc/show_errors.tcl:

Print file information:
RUN_IN_PLACE=no
LINUXCNC_DIR=
LINUXCNC_BIN_DIR=/usr/bin
LINUXCNC_TCL_DIR=/usr/lib/tcltk/linuxcnc
LINUXCNC_SCRIPT_DIR=
LINUXCNC_RTLIB_DIR=/usr/lib/linuxcnc/modules
LINUXCNC_CONFIG_DIR=
LINUXCNC_LANG_DIR=/usr/lib/tcltk/linuxcnc/msgs
INIVAR=inivar
HALCMD=halcmd
LINUXCNC_EMCSH=/usr/bin/wish8.6
LINUXCNC - 2.9.4
Machine configuration directory is '/home/kris/linuxcnc/configs/my_mill'
Machine configuration file is 'my_mill.ini'
INIFILE=/home/kris/linuxcnc/configs/my_mill/my_mill.ini
VERSION=1.1
PARAMETER_FILE=probe_basic.var
TPMOD=
HOMEMOD=
TASK=milltask
HALUI=halui
DISPLAY=probe_basic
COORDINATES=X Y Z
KINEMATICS=trivkins coordinates=XYZ
Starting LinuxCNC...
Starting LinuxCNC server program: linuxcncsvr
Loading Real Time OS, RTAPI, and HAL_LIB modules
Starting LinuxCNC IO program: iov2
Starting HAL User Interface program: halui
linuxcnc TPMOD=tpmod HOMEMOD=homemod EMCMOT=motmod
twopass:invoked with <> options
twopass:found ./main.hal
twopass:CANNOT FIND FILE FOR:io.hal
twopass:CANNOT FIND FILE FOR:io.hal
Shutting down and cleaning up LinuxCNC...
iov2: exiting
Removing HAL_LIB, RTAPI, and Real Time OS modules
Removing NML shared memory segments

Debug file information:
Note: Using POSIX realtime
2139
Stopping realtime threads
Unloading hal components
Note: Using POSIX realtime

---

Info report created by linuxcnc_info:
The file: /tmp/linuxcnc_info.txt
can be posted to a forum or a web site like:
pastebin.com
in order to provide information about the linuxcnc
system and configuration.

Date: Fri Nov 21 08:56:05 AM CST 2025
UTC Date: Fri Nov 21 02:56:05 PM UTC 2025
this program: /usr/bin/linuxcnc_info
uptime: 08:56:05 up 3 min, 1 user, load average: 1.44, 0.72, 0.30
lsb_release -sa: Debian Debian GNU/Linux 13 (trixie) 13 trixie
linuxcnc: /usr/bin/linuxcnc
pwd: /home/kris/linuxcnc/configs/my_mill
USER: kris
LOGNAME: kris
HOME: /home/kris
EDITOR:
VISUAL:
LANGUAGE:
TERM: dumb
COLORTERM:
DISPLAY: :0.0
DESKTOP: lightdm-xsession
display size: 1920x1080 pixels (509x286 millimeters)
PATH: /usr/bin:/home/kris/linuxcnc/configs/my_mill/bin:/usr/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games

uname items:
nodename -n: debian
kernel-name -s: Linux
kernel-vers -v: #1 SMP PREEMPT_RT Debian 6.12.48-1 (2025-09-20)
machine -m: x86_64
processor -p: unknown
platform -i: unknown
oper system -o: GNU/Linux

/proc items:
cmdline: BOOT_IMAGE=/boot/vmlinuz-6.12.48+deb13-rt-amd64 root=UUID=5efc6035-1184-4e51-acb6-e99aeeac4490 ro quiet isolcpus=3
model name: Intel(R) N100
cores: 4
cpu MHz: 1744.606
parport:
serial:

Versions:
gcc: gcc (Debian 14.2.0-19) 14.2.0
python: Python 3.13.5
git: not_in_PATH
git commit: NA
tcl: 8.6
/usr/bin/linuxcnc_info: line 159: wish: command not found
tk:
glade: not_in_PATH

linuxcnc_var all:

LINUXCNCVERSION: 2.9.4
LINUXCNC_AUX_GLADEVCP: /usr/share/linuxcnc/aux_gladevcp
LINUXCNC_AUX_EXAMPLES: /usr/share/linuxcnc/aux_examples
REALTIME: /usr/lib/linuxcnc/realtime
RTS: uspace
HALLIB_DIR: /usr/share/linuxcnc/hallib
PYTHON: /usr/bin/python3

dpkg -l '*linuxcnc*':
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===================-============-============-=====================================================================
un linuxcnc <none> <none> (no description available)
un linuxcnc-dev <none> <none> (no description available)
un linuxcnc-doc <none> <none> (no description available)
ii linuxcnc-doc-en 1:2.9.4-2 all motion controller for CNC machines and robots (English documentation)
un linuxcnc-doc-es <none> <none> (no description available)
un linuxcnc-doc-fr <none> <none> (no description available)
un linuxcnc-sim <none> <none> (no description available)
un linuxcnc-sim-dev <none> <none> (no description available)
ii linuxcnc-uspace 1:2.9.4-2 amd64 motion controller for CNC machines and robots
ii linuxcnc-uspace-dev 1:2.9.4-2 amd64 PC based motion controller for real-time Linux

Glad you got it working.

Внес исправления как написал, скомпилировал, запустил = РАБОТАЕТ! Ай да Пушкин, ай да сукин сын!
Made corrections as written, compiled, launched = WORKS! Oh yes Pushkin,

Links to the RaspOS image here too:
www3.langdonstaab.ca/iso/2025-11-11-rasp...-trixie-arm64.img.gz

MD5 sum (To check file integrity post-download):
www3.langdonstaab.ca/iso/2025-11-11-rasp...rc2-trixie-arm64.md5

Well a slightly newer version could work too.

Try whatever came right before "Bookworm", see if it's old enough.

Ubuntu 22.04 LTS with the 5.15 GA kernel seems to work well, even with old GPUs, and is supported until 2027, or until 2032 with Ubuntu Pro, plus a computer without internet should not need security updates at all.

I think it's really the kernel version that matters, but newer versions need a newer kernel, so that limits the OS version.

Try older versions 'till it works; there may or may not be a guide that states the maximum supported kernel version for your GPU.

With NVIDIA it's quite clear what's supported and what is not, AMD is lazy so far as drivers are concerned.

They release drivers when the card is first released, but don't seem to release drivers for any new OS after that release date.

hatte meine 7i92 auch letzte woche bekommen,
hab nicht viel getestet, aber läuft soweit.

probably, this is influenced only by that part of ini where the formula XXYYZ and then something like that? -


// Apply inverse matrix transform to the 3 cartesian coordinates
pos->tran.x = invdet * ( (e * i - f * h) * j[0]
+(c * h - b * i) * j[2]
+(b * f - c * e) * j[4]);

pos->tran.y = invdet * ( (f * g - d * i) * j[0]
+(a * i - c * g) * j[2]
+(c * d - a * f) * j[4]);

pos->tran.z = invdet * ( (d * h - e * g) * j[0]
+(b * g - a * h) * j[2]
+(a * e - b * d) * j[4]);

    // Pass rest of axes as identity
    //if (EMCMOT_MAX_JOINTS > 3) pos->a = j[3];
    //if (EMCMOT_MAX_JOINTS > 4) pos->b = j[4];
    if (EMCMOT_MAX_JOINTS > 5) pos->c = j[5];
    if (EMCMOT_MAX_JOINTS > 6) pos->u = j[6];
    if (EMCMOT_MAX_JOINTS > 7) pos->v = j[7];
    if (EMCMOT_MAX_JOINTS > 8) pos->w = j[8];

// Apply matrix transform to the 3 cartesian coordinates
j[0] = pos->tran.x * a + pos->tran.y * b + pos->tran.z * c;
j[1] = pos->tran.x * a + pos->tran.y * b + pos->tran.z * c;
j[2] = pos->tran.x * d + pos->tran.y * e + pos->tran.z * f;
j[3] = pos->tran.x * d + pos->tran.y * e + pos->tran.z * f;
j[4] = pos->tran.x * g + pos->tran.y * h + pos->tran.z * i;


    // Pass rest of axes as identity
   // if (EMCMOT_MAX_JOINTS > 3) j[3] = pos->a;
    //if (EMCMOT_MAX_JOINTS > 4) j[4] = pos->b;
    if (EMCMOT_MAX_JOINTS > 5) j[5] = pos->c;
    if (EMCMOT_MAX_JOINTS > 6) j[6] = pos->u;
    if (EMCMOT_MAX_JOINTS > 7) j[7] = pos->v;
    if (EMCMOT_MAX_JOINTS > 8) j[8] = pos->w;

?

This is certainly not a one-size-fits-all solution with automatic situation recognition, but for a specific situation