The other day, I took some dual ISO photos using the officially compiled atest Lua updates + fixes 500D firmware.
When I try to export using cr2hdr, I find that the DNG resolution after export is only 384x252

This is my log
cr2hdr: a post processing tool for Dual ISO images
Last update: ab1e90c on 2015-11-24 09:50:19 UTC by a1ex:
cr2hdr: moved safeguard from median_int_wirth to kth_smallest_i...
Active options:
--amaze-edge : use a temporary demosaic step (AMaZE) followed by edge-directed interpolation (default)
--cs2x2 : apply 2x2 chroma smoothing in noisy and aliased areas (default)
--no-bad-pix : disable bad pixel fixing (try it if you shoot stars)
--wb=graymax : set AsShotNeutral by maximizing the number of gray pixels (default)
Input file : C:\Users\Administrator\Pictures\2020\2020-10-01\IMG_0010.CR2
Camera : Canon EOS Kiss X3 (unknown, assuming 5D Mark III)
Full size : 4832 x 3204
Active area : 4770 x 3178
Black borders : 62 left, 26 top
Black level : 1016
ISO pattern : ddBB RGGB
White levels : 13296 11974
Noise levels : 8.01 7.67 26.63 25.98 (14-bit)
ISO difference : 4.04 EV (1645)
Black delta : 4.59
Black adjust : 72
Dynamic range : 10.65 (+) 8.68 => 12.72 EV (in theory)
AMaZE interpolation ...
Amaze took 2.62 s
Edge-directed interpolation...
Semi-overexposed: 1.99%
Deep shadows : 48.05%
Horizontal stripe fix...
26: offset too large (5559)
27: offset too large (5032)
Full-res reconstruction...
ISO overlap : 3.6 EV (approx)
Half-res blending...
Chroma smoothing...
Building alias map...
Filtering alias map...
Smoothing alias map...
Final blending...
Noise level : 88.04 (20-bit), ideally 87.94
Dynamic range : 13.12 EV (cooked)
Black adjust : -78
AsShotNeutral : 0.60 1 0.66, 4727K/g=1.40 (gray max)
Output file : C:\Users\Administrator\Pictures\2020\2020-10-01\IMG_0010.DNG
C:\Users\Administrator\Pictures\2020\2020-10-01\IMG_0010.DNG: copying EXIF from C:\Users\Administrator\Pictures\2020\2020-10-01\IMG_0010.CR2