FWIW = For What It's Worth
I only just discovered that the tiff-5.dll was missing from Windows Gimp 2.10.34 Checked nufraw in a standard Gimp and working. I do not know about the samj portable.
You might have problems with samj portable Gimp and RawTherapee or Darktable. I think Gimp will expect these as a regular installation. If you try any of the plugins check in Edit -> Preferences -> Import-Export, see that the appropriate plugin is selected.
Edit: Ok a try with samj 2.10.28 and nufraw. Put the nufraw folder in the Preferences > plug-ins folder same as any other plugin.
This importing a lumix .rw2 raw file. You can get it as 16 bit but no more.
..and changed the theme so you can see the plugin to mark as active.
I only just discovered that the tiff-5.dll was missing from Windows Gimp 2.10.34 Checked nufraw in a standard Gimp and working. I do not know about the samj portable.
You might have problems with samj portable Gimp and RawTherapee or Darktable. I think Gimp will expect these as a regular installation. If you try any of the plugins check in Edit -> Preferences -> Import-Export, see that the appropriate plugin is selected.
Edit: Ok a try with samj 2.10.28 and nufraw. Put the nufraw folder in the Preferences > plug-ins folder same as any other plugin.
This importing a lumix .rw2 raw file. You can get it as 16 bit but no more.
..and changed the theme so you can see the plugin to mark as active.