Firmware Upgrade and PWNCNC Spindle

gSender ❓ Question
1

I am about to update my SLB EXT on my Altmill I am using the PWNCNC 1.5 spindle which I have checked off as the MODVFD for spinsle 1.

I just want to make sure I am downloading the correct version of the latest fiemware. There are two choices.

1 - SLB EXT (AltMill):

  • Version 20260525
  • Newest, main version of grblHAL
  • Requires gSender 1.6.2 or newer
  • Unplug the VFD for firmware flashing

2 - SLB EXT (AltMill) ONLY for users with Huanyang or generic ‘MODVFD’ spindle setups:

  • Newest, main version of grblHAL
  • Requires gSender 1.6.0 or newer
  • Specific firmware require for use with Huanyang ‘V1’ or ‘P2A’ VFDs or generic spindles using ‘MODVFD’.
  • Read more about the use of the ‘MODVFD’ spindle profile for generic VFDs

I’m assuming number 2?

2

This is not really a gSender issue, but 20260525 main_grblHAL (option 1) has all spindles compiled in, including MODVFD thanks to some web builder updates - we’re no longer limited to only having 4 spindle options per build.

Screenshot 2026-06-16 at 4.28.53 PM
Screenshot 2026-06-16 at 4.28.53 PM344×193 7.05 KB

You’d just need to enable it as a selectable spindle in Config since only PWM is enabled by default.

The second option is no longer necessary and I’ve asked support to get it removed.

The first option should work for you.

3

Thanks for the quick response.