bootloaders: change instruction to match OSS release

Author: facchinm

bootloaders/PORTENTA_H33/README.md

@@ -0,0 +1,28 @@
+:floppy_disk: `bootloaders/PORTENTA_C33`
+====================================
+Compiled with
+```bash
+git clone https://github.com/arduino/arduino-renesas-bootloader
+git clone https://github.com/hathach/tinyusb
+cd tinyusb
+# This step is temporary
+patch -p1 < ../arduino-renesas-bootloader/0001-fix-arduino-bootloaders.patch
+python tools/get_deps.py ra
+cd ..
+cd arduino-renesas-bootloader
+TINYUSB_ROOT=$PWD/../tinyusb make -f Makefile.c33 
+```
+
+:rocket: `How to load bootloader`
+====================================
+
+Using any Portenta carrier **with USB A connector**, toggle the BOOT dip-switch, connect to the PC using a very uncommon USB-A to USB-A cable and reset the board. 
+The board will enumerate as Renesas RA USB Boot
+
+Then flash the bootloader with [`rfp-cli`](https://www.renesas.com/us/en/software-tool/renesas-flash-programmer-programming-gui#download)
+```
+rfp-cli -device ra -port $portname -p dfu_c33.hex
+```
+
+Otherwise, the same hex file can be loaded through the SWD port (using a Jlink for example)
+

bootloaders/PORTENTA_H33/README.txt

@@ -1,17 +1,17 @@
 :floppy_disk: `bootloaders/UNO_R4`
 ====================================
-Sources for Uno R4 WIFi at git@github.com:bcmi-labs/tinyusb.git , commit 185ae31ff15a1013a5a890455220a29bad1ed209
-
-Compiled with
-```bash
-cd examples/device/dfu && make BOARD=santiago_composta
-```
-
-Sources for Uno R4 Minima at git@github.com:bcmi-labs/tinyusb.git , commit b80fa8f4027c5aa4d9af5720a82e9238d8f792bb
-
 Compiled with
 ```bash
-cd examples/device/dfu && make BOARD=santiago
+git clone https://github.com/arduino/arduino-renesas-bootloader
+git clone https://github.com/hathach/tinyusb
+cd tinyusb
+# This step is temporary
+patch -p1 < ../arduino-renesas-bootloader/0001-fix-arduino-bootloaders.patch
+python tools/get_deps.py ra
+cd ..
+cd arduino-renesas-bootloader
+TINYUSB_ROOT=$PWD/../tinyusb make -f Makefile.minima 
+# TINYUSB_ROOT=$PWD/../tinyusb make -f Makefile.wifi
 ```
 
 :rescue_worker_helmet: `How to update ESP32-S3 firmware`