Works fine following these steps: 0) Copied .fw firmware file from driver installed in Windows. 1) Added my scanner to */etc/sane.d/gt68xx.conf*:
... # Autodetect Xerox 7600 usb 0x04a7 0x04a6 override "plustek-opticslim-2400" For some reason, the scanner is idle for about 20 seconds before each scan, adjusting the exposure, so I had to hardcode some settings and remove the automatic adjustment of these parameters. 2) Commented lines 1885-1912 <https://gitlab.com/sane-project/backends/-/blob/master/backend/gt68xx_high.c#L1885> in sources (*sane-backends/backend/gt68xx_high.c*). 3) Commented lines 1917-1940 <https://gitlab.com/sane-project/backends/-/blob/master/backend/gt68xx_high.c#L1914> in the same file. 3) Added this code in the same file starting with line 1914 <https://gitlab.com/sane-project/backends/-/blob/master/backend/gt68xx_high.c#L1914> : if (!red_done || !green_done || !blue_done) { DBG (0, "gt68xx_afe_cis_auto: setting AFE reached limit\n"); DBG (0, "gt68xx_afe_cis_MOD: exposed custom values\n"); *afe->r_offset = 13; afe->g_offset = 15; afe->b_offset = 16; afe->r_pga = 3; afe->g_pga = 4; **afe->b_pga = 5;* gt68xx_afe_cis_adjust_gain_offset ("red", &values, r_obuffer, r_gbuffer, afe, &old_afe); gt68xx_afe_cis_adjust_gain_offset ("green", &values, r_obuffer, r_gbuffer, afe, &old_afe); gt68xx_afe_cis_adjust_gain_offset ("blue", &values, r_obuffer, r_gbuffer, afe, &old_afe); } 4) Also commented the lines 1946-1952 <https://gitlab.com/sane-project/backends/-/blob/master/backend/gt68xx_high.c#L1946> (in the same file, of course) trying to save the settings (as I understand it, the program cannot do this, so the program adjusts them again every time ¯\_(ツ)_/¯ )
