diff --git a/README.md b/README.md
index 7b4112f..f34ea9b 100644
--- a/README.md
+++ b/README.md
@@ -42,3 +42,12 @@ git annex pull
 git annex addurl https://github.com/Dasharo/meta-dts/releases/download/v2.1.3/dts-base-image-v2.1.3.wic.gz --file=dts/dts-base-image-v2.1.3.wic.gz
 git annex addurl http://www.tinycorelinux.net/15.x/x86/release/TinyCore-15.0.iso --file iso/TinyCore-15.0.iso
 ```
+* Delete file permanently - use with caution:
+
+```bash
+git annex drop --force FILE_NAME
+git annex whereis FILE_NAME                 # list of all copies known by annex
+git annex drop --force FILE_NAME --from web # execute this line for each repository listed, web is one to use with http(s) links
+rm FILE_NAME
+git annex sync
+```
diff --git a/secure-boot/README.md b/secure-boot/README.md
index a486fe0..6307542 100644
--- a/secure-boot/README.md
+++ b/secure-boot/README.md
@@ -1,7 +1,9 @@
 # Secure Boot
 
-## sb_test_BAD_INFLUE.img
+## sb_test_data.img
 
-* Content: files from `../hello-dasharo/dist` directory
-* Building: run `create_img.sh`
+* Single FAT32 partition, labeled BAD_INFLUE, on MBR disk image
+* Contains files from `../hello-dasharo/dist` directory
+* Run `create_img.sh` to re-create
+* Can be safely transferred with dd command to USB stick