diff --git a/docs/Hardware/GPIO_35.md b/docs/Hardware/GPIO_35.md
index 2d510f12..b9fc933f 100644
--- a/docs/Hardware/GPIO_35.md
+++ b/docs/Hardware/GPIO_35.md
@@ -1,6 +1,8 @@
 
 How i installed the 3.5" (A) type of screen on RaspberryOS Bookworm (Debian 12)
 
+Update: I've tested Bullseye (Debian 11) and it works, but [rotation was not working](#rotation)
+
 ![preview](../img/hardware/rpi35a.jpg)
 
 !!! abstract "Disclaimer"
@@ -41,27 +43,45 @@ sudo reboot
 
 Some screens will not behave correctly and/or display wrong colors,
 this usually due to the wrong [SPI](https://en.wikipedia.org/wiki/Serial_Peripheral_Interface) speed
-In my case the maximum i could achieve is 22.22Mhz (400mhz core / 18)
+In my case the maximum i could achieve is 22.22Mhz
 ```
 dtoverlay=piscreen,drm,speed=22222222
 ```
-As you may predict speed has a big impact in usability as it dictates how often the display will refresh
+
+??? info "About speed"
+
+    As you may predict speed has a big impact in usability as it dictates how often the display will refresh
+
+    If i understand the [involved drivers](https://github.com/torvalds/linux/blob/65d287c7eb1d14e0f4d56f19cec30d97fc7e8f66/drivers/spi/spi-bcm2835.c#L1068)
+    correctly, the spi speed is calculated as:
+    `core_clock / core_divisor`
+
+    The divisor must be a multiple of 2, that ranges between 2 and 65536
+
+    Core clock in the case of Pi 3 would be 400mhz
+
+    So even if you can enter any number, it will be approximated to a value from that formula
+
+    That's why i used 22.222.222 (400 / 18)
 
 reboot to test any changes.
 
 ## Rotation
 
-!!! bug
-    The current Rpi Kernel v6.1.77 has a bug in the dtb and rotate doesn't work, fix has been merged in v6.6
-    you can copy the dtb from the new kernel into the old one if needed
-
-
 You can rotate the screen adding a rotate line with the degrees [0, 90, 180, 270]
 ```
 dtoverlay=piscreen,drm,rotate=180
 ```
 Screen rotation will require adjusting the touch matrix see [Touch issues](../../Troubleshooting/Touch_issues/)
 
+!!! bug
+
+    Raspberry linux Kernel v6.1.77 has a bug in the dtb and rotate doesn't work
+
+    The fix has been merged in linux v6.6
+
+    you can copy the dtb from the new kernel into the old one if needed
+
 ## Console
 
 To make the console work: