UPDATE 5/28/13 - There will be no further development on this thread. Verygreen has changed his SD scheme and they no longer work on this system and Bokbokan has started to develop his own HD+ Hybrid which is better than mine. The Cyanoboot menu works on his and the ROMs come ready for his Hybrid. See his thread here. Some of the other zips on this thread will still work with bokbokan's new HD+ Hybrid.
You can still use this Hybrid on verygreen's Legacy SD ROMs up to 5/29/13 (Legacy only)
If you want to use the Hybrid and you already have an Original SD installation, you must abandon your current SD setup and start with a fresh re-burn of the card. You can use your old CWM (Clockworkmod recovery) on SD to back up your old Original SD installation. Then later, after flashing the ROM on the new SD, you can use your new CWM to do an advanced restore to restore your data. Then your apps and settings will remain.
I do not have the cyanoboot menu working like bokbokan does on the HD, but I have modified the bootloader to be able to manually choose stock or CM when the cyanoboot logo is up. See the section below about booting between ROMs.
Setting up the SD
Begin by downloading the files you need either with stock or your PC. You will need my Hybrid SD image file, attached below, my Hybrid SD CM ROM Converter zip, also attached below, the CM ROM zip you want to install and the gapps zip to match it. Put the last three zips on your internal media sdcard that is built into your Nook. To get them on the internal SD, just download the zips with stock to internal SD or hook your cable to the PC with stock booted and copy to internal SD. You can get the HD+ CM10 ROMs here and the HD+ CM10.1 ROMs here. You can get the gapps zips here, 20121011 for CM10 and 20121212 for CM10.1.
Extract the Hybrid SD image zip and you will have a 117MB .img file. Burn that to your SD with Win32DiskImager in Windows or the dd command in Linux or OSX. The SD can be as small as 2GB. The size does not effect the amount of apps you can install, but the bigger the card, the more media storage space you will have.
To use Win32DiskImager, find it on the web (here, it's free) and install it on your Windows PC. Open it (be sure to run it as administrator) and select the drive (device) that has your card reader with your SD inserted. Then in the image file box put the location where you have the extracted img file. Then when everything is set right, click on the write button. A warning will pop up asking if you want to proceed. When you have verified that you are going to write to the correct device, click on Yes. (One user overwrote their external USB hard drive by not verifying first). If you get an error message about access denied, it means you are looking at the drive with Windows Explorer. Close Windows Explorer and try again. In fact, it is a good idea to close all unnecessary windows when burning, even your browser.
When burning is complete, insert the SD into the Nook and boot. It should boot to the cyanoboot logo and sit there for a little while while it creates the other partitions on the SD. Then it will reboot on its own and take a little more time as it formats the CM10SDCARD partition. Then it will end up in CWM for HD+ Hybrid SD. To use CWM, press the volume up/down keys to move the cursor and the n key to select an item. The power key is the back button.
You can use the "install zip from SD/choose zip from internal memory" option to flash the CM ROM you downloaded earlier to your internal memory sdcard. After flashing the ROM and before rebooting, flash my Hybrid SD CM ROM Converter zip. It will make the necessary changes to the ROM to make it work on the Hybrid SD. If you forget to do this, it will hang in the boot animation forever when you reboot. To fix it, you can reboot to CWM to flash the Converter zip. Power off and while rebooting, wait for the small flash and the cyanoboot logo to show, then hold the power and n for a few seconds, let go of power so it does not turn itself off but keep holding n for a few more seconds and then let it go too. It should boot to CWM. Once back in CWM you can flash the converter zip and it should boot ok.
Optionally you can flash the right version of gapps to match your ROM. Gapps can be flashed any time after the ROM is flashed, before or after the converter zip, or even after booting.
When you reboot (you need to leave the SD in the slot), the CM ROM should start. Set it up however you want with your apps and Play Store if you flashed gapps. You can restore your apps with Titanium Backup if you used it. Or you can use the new CWM to do an advanced restore of /data of a prior nandroid backup of your SD installed CM to get your apps and settings back.
If you later want to upgrade your ROM to another build, download it to your CM10SDCARD partition using CM. Then boot to CWM and flash it. Again, immediately flash the converter zip.
UPDATE 5-14-13 - As of 5/5/13 verygreen changed the ramdisk so that the ROM no longer worked on Hybrid. I have now fixed that with rev 3 of the converter zip.
Booting between ROMs
I now have modified the bootloader to be able to boot back to stock. All you have to do is flash the latest version of the Converter zip attached below. It will add the new files necessary to make it work. You can do it even if you have already flashed the rev1 zip. It is not a complete boot menu, but is very simple to operate and it works with verygreen's new kernels. If you want to boot to CM on SD, do nothing and it will boot there automatically. If you want to boot to stock, hold the n key while the cyanoboot logo first comes up and it will boot to stock. And if you hold the n and power key, it will boot to CWM. You can still use the Quick Boot app as discussed in the next paragraph. It still works, there is just the extra step of holding the n key on booting to stock.
To make rebooting between Stock and CM easy, install an app from the Play Store called Quick Boot by Sirius Software. It is free. You can configure the menu choices. I set mine up for Reboot, Bootloader and Power Off. Reboot starts CM, Bootloader starts Stock (but with the new CM10 kernels, you must press the n key when the cyanoboot logo comes up) and of course Power Off turns off the device. I install this on both systems and it allows me to boot back and forth. The app will not run properly on Stock unless it is rooted.
If I want to go to SD recovery (CWM), the Quick Boot recovery option does not work, so I boot to CM and use the power off/reboot menu to select reboot to recovery. If the reboot to recovery option does not display, go to settings, about tablet and tap the build number several times. That will activate development options. Go to that. Then put a check in the Advanced reboot checkbox. Then when you hold the power button and the power off menu pops up, you can select reboot followed by recovery and it will boot to CWM.
Or you could just hold the power + n keys for a few seconds while the cyanoboot first starts. Wait for the cyanoboot logo to show, then press the power and n button together for a few seconds, then release the power button followed by the releasing the n button. It should boot to CWM. If it boots to stock or CM, you did not get the timing right. Try again. If it boots to stock recovery and asks if you want to erase data, click on exit and try again.
I believe the below modifications will still work on Bokokan's HD+ Hybrid. They worked on his HD version so they should work on his HD+ version, but I have not tested them.
Optional Modification to allow Stock to use the Hybrid SD for media storage.
If you want to use the Hybrid sdcard partition to store your media files while running stock, flash one of the four zips I made to help with that. They can be flashed with either the CM Hybrid CWM or my stock CWM. I have them hard coded so they will only effect the settings on stock. One zip, NookHD-HDplus-stock-fix-vold-for-dual-boot-hybrid.zip, will set stock so that it sees the Hybrid SD partition 3 (CM10SDCARD) as ext_sdcard under stock. That way you can access the files that CM puts there and CM can access the files stock puts there. Another zip, NookHD-HDplus-stock-fix-vold-for-dual-boot-hybrid-swapped.zip, will do the same thing but have ext_sdcard and sdcard swapped on stock much like my SDswap zip did. And a third zip, NookHD-HDplus-stock-return-vold-to-stock-settings.zip, will take stock back to the original settings if you want to use an ordinary SD with it. A fourth zip will remove the SDswap feature in stock if you installed it and want to leave the ability to see the Hybrid SD CM10SDCARD partition with stock.
New Stock CWM modified to be compatible with the Hybrid
This setup uses more of your internal data space so if you use older stock CWMs it means larger stock backups as it will backup the SD information along with the stock information. And if you wipe /data with the old CWM it will delete your new SD files. And if you restore an older stock backup with the old CWM, it will overwrite your SD files. I have modified the stock CWM so that when it wipes /data or backs up/restores /data it ignores and does not touch the information stored there for the SD operation. And you can restore old stock backups with the new stock CWM without worry. You can get the new rev3 of HD+ CWM for stock on my HD/HD+ CWM thread.
Swapping emmc and CM10SDCARD
Some users have a small SD card and want their apps to use the large internal media storage to store their data. I have developed a couple of zips to swap the internal and external SDs when booted to CM so your apps can use internal memory, one to add the swap and one to remove it. Get them attached below.
These zips can be flashed with CWM but will only install to the HD/HD+ Hybrid SD with CM. I just added rev2 which fixes a bug. If you already flashed rev0 or rev1, you need to flash the remove zip before you flash the rev2.
With rev2, both SDCARD and EMMC will show internal media storage, as will both MTP folders. A new folder, called ext_sdcard, will show the external Hybrid media partition.
I removed the manual instructions, it got too complicated.
Hybrid on the HD
Big thanks goes to bokbokan for working out the details of this scheme on the HD. All I did was adapt it to the HD+. For those of you with an HD and you have not read about bokbokan's Hybrid for the HD, you can read about it and get his image zip here. But his Hybrid only works on his CM10.1 ROMs. But with his CM10.1, there is no need to convert them. His has them all ready for his Hybrid setup. You can get his ROMs here. You can use my vold zips posted here for modifying stock to see his Hybrid SD, they work on both devices. And you can get rev3 of my stock HD CWM that has been modified to be compatible with his Hybrid SD on my HD/HD+ CWM thread linked in my signature.
I have tested this setup on both CM10 and CM10.1. It definitely runs faster and is more stable. I even have been using it on my PNY 8GB card that I could not even get to work with CM 7.2 on my Nook Color. It runs great now. And I tried the 1/20 version of CM10 that rebooted on me four times the first day I tried that version on my old setup. It has not rebooted once on this setup.
And I just tested it on a 2GB SD. It installs and runs fine. The only difference is it only has a 1GB CM10SDCARD partition.
But it is a work-in-progress so there may be bugs. If you have feedback or questions, reply to this thread. If you are a new user and cannot post here, post on my HD/HD+ tips thread here. Please do not send me private messages or emails. By posting in the forums others get a chance to help you and if I answer your question in the forum, others can see my response and it may help them too. If you post comments on verygreen's ROM threads, be sure to mention you are running his ROM on the Hybrid, including any special modifications you may have made here, like running different kernels.