diff --git a/README.md b/README.md
index afaf56d..5866e26 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,14 @@
 # nanopi-r4s
-debian arm64 linux for the nanopi r4s
+stock debian arm64 linux for the nanopi r4s
 
 ---
-### debian bullseye setup
+### debian bookworm setup
 
 <br/>
 
 **1. download image:**
 ```
-wget https://github.com/inindev/nanopi-r4s/releases/download/v11.4/bullseye.img.xz
+wget https://github.com/inindev/nanopi-r4s/releases/download/v12-rc1/bookworm.img.xz
 ```
 
 <br/>
@@ -24,7 +24,7 @@ ls: cannot access '/dev/sd*': No such file or directory
  * after plugging-in device:
 ```
 ls -l /dev/sd*
-brw-rw---- 1 root disk 8, 0 Jul  2 16:33 /dev/sda
+brw-rw---- 1 root disk 8, 0 Mar  7 03:14 /dev/sda
 ```
 * note: for mac, the device is ```/dev/rdiskX```
 
@@ -32,7 +32,7 @@ brw-rw---- 1 root disk 8, 0 Jul  2 16:33 /dev/sda
 
 **3. in the case above, substitute 'a' for 'X' in the command below (for /dev/sda):**
 ```
-sudo sh -c 'xzcat bullseye.img.xz > /dev/sdX && sync'
+sudo sh -c 'xzcat bookworm.img.xz > /dev/sdX && sync'
 ```
 
 #### when the micro sd has finished imaging, eject and use it to boot the nanopi r4s to finish setup
@@ -99,8 +99,8 @@ usb emmc (nand flash) drive.
 
 **1. download images:**
 ```
-wget https://github.com/inindev/nanopi-r4s/releases/download/v11.4/usb_rksd_loader.img
-wget https://github.com/inindev/nanopi-r4s/releases/download/v11.4/usb_u-boot.itb
+wget https://github.com/inindev/nanopi-r4s/releases/download/v12-rc1/usb_idbloader.img
+wget https://github.com/inindev/nanopi-r4s/releases/download/v12-rc1/usb_u-boot.itb
 ```
 
 <br/>
@@ -126,8 +126,7 @@ brw-rw---- 1 root disk 8, 0 Jul  2 16:33 /dev/sda
 ```
 cat /dev/zero | sudo tee /dev/sdX
 sudo dd bs=4K seek=8 if=usb_rksd_loader.img of=/dev/sdX conv=notrunc
-sudo dd bs=4K seek=2048 if=usb_u-boot.itb of=/dev/sdX conv=notrunc
-sync
+sudo dd bs=4K seek=2048 if=usb_u-boot.itb of=/dev/sdX conv=notrunc,fsync
 ```
 
 #### when the micro sd has finished imaging, eject and use it to boot the nanopi r4s to usb
@@ -136,13 +135,13 @@ sync
 
 
 ---
-### building debian bullseye arm64 for the nanopi r4s from scratch
+### building debian bookworm arm64 for the nanopi r4s from scratch
 
 <br/>
 
 The build script builds native arm64 binaries and thus needs to be run from an arm64 device such as a raspberry pi4 running 
 a 64 bit arm linux. The initial build of this project used a debian arm64 raspberry pi4, but now uses a nanopi r4s running 
-pure debian bullseye arm64.
+pure debian bookworm arm64.
 
 <br/>
 
diff --git a/debian/README.md b/debian/README.md
index 113552e..b734f97 100644
--- a/debian/README.md
+++ b/debian/README.md
@@ -1,8 +1,34 @@
-#### <i>Note: This script should be run from an arm64 device such as a raspberry pi4.</i>
+## stock debian bookworm linux for the nanopi r4s
+
+<i>Note: This script is intended to be run from a 64 bit arm device such as an odroid m1 or a raspberry pi4.</i>
 
 <br/>
 
+**build debian bookworm using debootstrap**
 ```
 sudo sh make_debian_img.sh
 ```
 
+<i>the build will produce the target file mmc_2g.img.xz</i>
+
+<br/>
+
+**copy the image to mmc media**
+```
+sudo sh -c 'xzcat mmc_2g.img.xz > /dev/sdX && sync'
+```
+
+<br/>
+
+**multiple build options are available by editing make_debian_img.sh**
+```
+media='mmc_2g.img' # or block device '/dev/sdX'
+deb_dist='bookworm'
+hostname='deb-arm64'
+acct_uid='debian'
+acct_pass='debian'
+enterprise_dtb='true'
+disable_ipv6='true'
+extra_pkgs='pciutils, sudo, wget, u-boot-tools, xxd, xz-utils, zip, unzip'
+```
+
diff --git a/dtb/README.md b/dtb/README.md
new file mode 100644
index 0000000..316f162
--- /dev/null
+++ b/dtb/README.md
@@ -0,0 +1,27 @@
+## linux device tree for the nanopi r4s
+
+<br/>
+
+**build device tree images for the nanopi r4s**
+```
+sh make_dtb.sh
+```
+
+<i>the build will produce the target files: rk3399-nanopi-r4s.dtb and rk3399-nanopi-r4s-enterprise.dtb</i>
+
+<br/>
+
+**optional: create symbolic links**
+```
+sh make_dtb.sh links
+```
+
+<i>convenience link to various rk3399 device tree files will be created in the project directory</i>
+
+<br/>
+
+**optional: clean target**
+```
+sh make_dtb.sh clean
+```
+
diff --git a/uboot/README.md b/uboot/README.md
new file mode 100644
index 0000000..f09334e
--- /dev/null
+++ b/uboot/README.md
@@ -0,0 +1,29 @@
+## u-boot 2023.01 for the nanopi r4s
+
+<i>Note: This script is intended to be run from a 64 bit arm device such as an odroid m1 or a raspberry pi4.</i>
+
+<br/>
+
+**1. build u-boot images for the nanopi r4s**
+```
+sh make_uboot.sh
+```
+
+<i>the build will produce the target files idbloader.img, and u-boot.itb</i>
+
+<br/>
+
+**2. copy u-boot to mmc or file image**
+```
+dd bs=4K seek=8 if=idbloader.img of=/dev/sdX conv=notrunc
+dd bs=4K seek=2048 if=u-boot.itb of=/dev/sdX conv=notrunc
+sync
+```
+
+<br/>
+
+**4. optional: clean target**
+```
+sh make_uboot.sh clean
+```
+