diff --git a/build_arm_image/README.md b/build_arm_image/README.md
index d3019b4..1e739ca 100644
--- a/build_arm_image/README.md
+++ b/build_arm_image/README.md
@@ -50,9 +50,9 @@ Usage:
 
 It takes some minutes to perform all the steps (~ 2m3.867s at last run). Be patient.
 
-Use `df` or `lsblk` to find the name of your sdcard device. The script is taking care of umonting the partition if any. It also guesses the disk's name if you give an partition's name instead of entire disk device's name.
+Use `df` or `lsblk` to find the name of your sdcard device. The script is taking care of umonting the partition if any. It also guesses the disk's name if you gave a partition's name instead of entire disk device's name.
 
-Be carefull not to wipe the wrong device!
+BE CAREFULL not to wipe the wrong device!
 
 #### 02_install_yunohost.sh
 
@@ -80,6 +80,16 @@ Run:
 ./02_install_yunohost.sh 192.168.1.123
 ~~~
 
+This step is quite long. It took ~24min on my Raspberry. Be patient, A message will be displayed on the screen to explain how you can watch it if you want.
+
+If you got ssh `Host key verification failed.`, fix it then:
+
+~~~bash
+rm _build_arm_steps/yuno_step*
+# retry
+./02_install_yunohost.sh 192.168.1.123
+~~~
+
 #### 03_copy_sdcard_to_img.sh
 
 When the build is finished the Raspberry will shutdown. Unplug and insert the sdcard back in the computer.