gPhoto2 and libgphoto for n800
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02-25-2012 , 05:52 PM
Posts: 154 | Thanked: 72 times | Joined on Jan 2009 @ Toronto
The MUSB controller used on N8x0 resembles the proverbial man with a hammer who sees every problem as a nail. The hammer in this case is the controller's ability to mount USB devices automatically if they use the HID protocol or the Mass Storage protocol. Presented with a USB device that uses a different protocol, the controller just keeps banging away until the battery drains and the tablet crashes, often with an audible "pop".
There are standard ways of suppressing unwanted automounting by host controllers such as OHCI, EHCI etc. gphoto2 does that, but it doesn't work with this MUSB controller (which is an otg controller, not true host).
If you want to run gphoto2 on a Maemo tablet, making use of your N800, your best bet is as follows:
1. Install 0xFFFF.static on your N800.
2. Buy a barely-used Nokia 770 for under $50.
3. Also buy the following, if you don't have them already:
(i) USB power source;
(ii) USB power-data Y cable (A male to mini B data, plus A male power only)
- this often comes supplied with a USB HDD enclosure, or from eBay for about $2.
(iii) USB gender changer female x female;
(iv) 2 GB mmcMobile card.
4. Flash OS2008HE to the 770 and clone the rootfs to a large partition (768 MB or more) on the mmc.
(Cloning is not really essential, so long as you install very little other than gphoto2 on the internal flash.)
5. Download gphoto2 from
and use "Install from file" in the App Manager to install it on the 770 (in whichever OS2008HE rootfs you want to use).
6. Use the 0xFFFF flasher on your N800 to enable USB host mode on the 770. You have to remove the mmc in order to use the flasher, but see the following comment in parenthesis.
(This modifies the initfs so that any rootfs on the 770 will boot up in host mode, whether on the internal flash or the mmc. At this point, the 770 has no USB function at all, because there is no power to its USB transceiver.)
7. While the 770 is running, use the Y cable and power source to supply USB power to it.
DO NOT ATTACH ANYTHING TO THE OTHER DATA END BEFORE CONNECTING THE 770 TO THE POWER SOURCE.
The 770 is now in host mode with OHCI (low speed) controller. You can confirm this by running dmesg, if you like. Keyboards and mice work automatically, but memory devices must be mounted by the "mount" command. gphoto2 does its own mounting, according to the task at hand.
8. Attach your camera, using the gender changer if needed.
9. Run gphoto2.
Last edited by scaler; 02-25-2012 at
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