Aura HD Modifying VCOM for refurbished device

MarkWilliams · Today, 06:40 AM

I have an official Kobo refurbished Aura HD. I don't know if the screen was replaced or not, but screen contrast is poor compared to my Mini. I notice than on images I cannot see all the grey levels.
I wonder if the VCOM level has been set correctly so I open the device and checked the label, which is -2.20 .

I inspected the appropriate bytes in /dev/mmcblk0 but they were set to 00, so I changed them to FF2A, which corresponds to -220. I can verify the change with ntx_hwconfig but the contrast does not appear to improve after a reboot.

Should I modify the values further, or try a different approach. Is it possible to verify the waveform?

Today, 06:40 AM	#1
MarkWilliams Junior Member Posts: 5 Karma: 10 Join Date: May 2015 Device: Kobo Touch	Modifying VCOM for refurbished device I have an official Kobo refurbished Aura HD. I don't know if the screen was replaced or not, but screen contrast is poor compared to my Mini. I notice than on images I cannot see all the grey levels. I wonder if the VCOM level has been set correctly so I open the device and checked the label, which is -2.20 . I inspected the appropriate bytes in /dev/mmcblk0 but they were set to 00, so I changed them to FF2A, which corresponds to -220. I can verify the change with ntx_hwconfig but the contrast does not appear to improve after a reboot. Should I modify the values further, or try a different approach. Is it possible to verify the waveform?

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