[Nook Color Android Development] leapinlar:
I thought I would share something that I finally figured out. I have been trying to find a way to mount the sd card boot partition without removing the card or booting to emmc. I wanted to do this so that I could download the nightly on the nook and put it directly in the boot partition. I figured out a way and it works great.

Use a root file manager to create a new folder in /data. I called mine sdboot. Then create a blank text file. I named mine 19mountsdboot (with no .txt on the end!). Then I put the following text in it and saved it:

#!/system/bin/sh

# mount SD boot partition

busybox mount -t vfat /dev/block/mmcblk1p1 /data/sdboot;

Copy that new file to the /etc/init.d folder using your root file manager. Change the permissions to match the other files there. Now reboot the nook.

When finished booting, you should be able to use your root file manager to go to /data/sdboot. And you should see your boot files there. (Don't mess with them.)

Now you can copy the nightly zip there. Then reboot to the verygreen recovery and your nightly should install.

All this without taking the card out or booting to emmc or hooking up to your PC. And it should stay that way even after flashing new nightlies to the sd.

Edit: I attached the file here in case people were having trouble getting it right. Just unrar and put in the /etc/init.d folder and change permissions. You still need to create the folder in /data first.

EDIT 2: I just modified the file to automatically create the directory and mount it. Just unrar and put the file in /etc/init.d folder and fix permissions. No need to create the new folder. Or better yet, I created a flashable install zip that does everything for you. You only need to flash it once (for SD installs). It will survive flashing of new SD nightlies. It can also be flashed to emmc and will mount the SD boot partition, but only if an SD install SD is in the slot. It will recognize an ordinary SD and not try to mount the SD boot partition. However, if you want to keep this on emmc, reflash after every emmc nightly flash.

EDIT 3: Just found a problem with the install zip. Needed to have the permissions set properly. Should be all fixed now. Use the rev. 1 zip

EDIT 4 (6-13-12): Added Rev 2 of the script and install zip. Rev 2 adds a symlink to the root directory so that 'sdboot' shows up in the root directory as well as in /data/sdboot. You can manually install the script to the /system/etc/init.d folder. Just unrar it and put it in that folder and set the permissions to execute. If you do not feel comfortable manually installing the script, put the zip in the boot partition and reboot to recovery and it will install it automatically for you. And you do not have to re-flash again after a new ROM flash. (If you previously had installed a prior version to /data/local/init.d, manually remove it before you flash the new version. If you don't you will have two copies on your system and that sometimes causes Root Explorer to lock up.) This version works great to direct download your new zip to sdboot with the new Goo Manager. Just change Goo Manager's download directory to /sdboot/ and it will put it on your boot partition.