diff --git a/software/bootldr/Makefile b/software/bootldr/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..277c9d97d504d26b6a3499d455039fd94f0202a0
--- /dev/null
+++ b/software/bootldr/Makefile
@@ -0,0 +1,42 @@
+#CROSS_COMPILE_TARGET ?= /home/mattia/riscv-toolchain/riscv/bin/riscv32-elf-
+
+CROSS_COMPILE_TARGET ?= /home/mattia/riscv32-nanolib/gnu-mcu-eclipse/riscv-none-gcc/8.1.0-2-20181019-0952/bin/riscv-none-embed-
+CFLAGS += -mabi=ilp32 -march=rv32im -Os -ffunction-sections -fdata-sections --specs=nano.specs --specs=nosys.specs -lgcc -lc -Wl,--gc-sections
+
+
+CC = $(CROSS_COMPILE_TARGET)gcc
+LD = $(CROSS_COMPILE_TARGET)ld
+OBJDUMP = $(CROSS_COMPILE_TARGET)objdump
+OBJCOPY = $(CROSS_COMPILE_TARGET)objcopy
+SIZE = $(CROSS_COMPILE_TARGET)size
+STRIP = $(CROSS_COMPILE_TARGET)strip
+
+
+
+all: bootloader.hex
+
+crt0.o: crt0.S
+ $(CC) -c -o $@ $(CFLAGS) $<
+
+irq.o: irq.S
+ $(CC) -c -o $@ $(CFLAGS) $<
+
+eth_config.o: eth_config.c
+ $(CC) -c -o $@ $(CFLAGS) $<
+
+refresh.o: refresh.s
+ $(CC) -c -o $@ $(CFLAGS) $<
+
+main: main.o crt0.o bootldr.ld
+ $(CC) -o $@ -nostartfiles $(CFLAGS) crt0.o main.o -T bootldr.ld
+
+main-text.bin: main
+ riscv32-elf-objcopy -j .text -j .loader -O binary $< $@
+
+bootloader.hex: main-text.bin
+ riscv32-elf-objcopy -I binary -O ihex $< $@
+
+clean:
+ rm main
+ rm main-text.*
+ rm bootloader.*
diff --git a/software/bootldr/bootldr.ld b/software/bootldr/bootldr.ld
new file mode 100644
index 0000000000000000000000000000000000000000..9f4c4897df4288b7aec1818bb38de530b1c396a1
--- /dev/null
+++ b/software/bootldr/bootldr.ld
@@ -0,0 +1,75 @@
+OUTPUT_FORMAT("elf32-littleriscv")
+ENTRY(_start)
+
+MEMORY
+{
+ iram : ORIGIN = 0x00000000, LENGTH = 512
+ ldr : ORIGIN = 0x00000200, LENGTH = 512
+ dram : ORIGIN = 0x00010000, LENGTH = 64K
+
+}
+
+
+SECTIONS
+{
+
+ /* Begining of code and text segment */
+ . = 0x00000000;
+ /* text: Program code section */
+ .text :
+ {
+ *(.boot)
+ *(.text)
+ *(.text.*)
+ *(.gnu.linkonce.t.*)
+
+ } > iram
+ .loader :
+ {
+ *(.launcher)
+ *(.launcher.*)
+ *(.launcher_call)
+ } > ldr
+
+ /* rodata: Read-only data */
+ .data :
+ {
+ *(.rdata)
+ *(.rodata)
+ *(.rodata.*)
+ *(.gnu.linkonce.r.*)
+ *(.data)
+ *(.data.*)
+
+ *(.gnu.linkonce.d.*)
+ _edata = .;
+
+ /* Have _gp point to middle of sdata/sbss to maximize displacement range */
+ . = ALIGN(16);
+ _gp = . + 0x800;
+
+ *(.sdata)
+ *(.sdata.*)
+ *(.srodata.*)
+ *(.gnu.linkonce.s.*)
+
+ . = ALIGN(8);
+ _fbss = .;
+
+ *(.sbss)
+ *(.sbss.*)
+ *(.gnu.linkonce.sb.*)
+
+ _bss_start = .;
+
+ *(.bss)
+ *(.bss.*)
+ *(.gnu.linkonce.b.*)
+ *(COMMON)
+
+ _end = ALIGN(8);
+ } > dram
+
+ PROVIDE(_fstack = ORIGIN(dram) + LENGTH(dram) - 0x100);
+
+}
diff --git a/software/bootldr/crt0.S b/software/bootldr/crt0.S
new file mode 100644
index 0000000000000000000000000000000000000000..798083d7fa8dbc83f0999481e74d494d05aeef23
--- /dev/null
+++ b/software/bootldr/crt0.S
@@ -0,0 +1,81 @@
+ .section .boot, "ax", @progbits
+
+.global _start
+_start:
+ j _entry
+
+.org 0x8
+
+
+
+_entry:
+
+
+
+ lui ra, 0
+ lui sp, 0
+ lui gp, 0
+ lui tp, 0
+ lui s0, 0
+ lui s1, 0
+ lui s2, 0
+ lui s3, 0
+ lui s4, 0
+ lui s5, 0
+ lui s6, 0
+ lui s7, 0
+ lui s8, 0
+ lui s9, 0
+ lui s10, 0
+ lui s11, 0
+ lui t0, 0
+ lui t1, 0
+ lui t2, 0
+ lui t3, 0
+ lui t4, 0
+ lui t5, 0
+ lui t6, 0
+ lui a0, 0
+ lui a1, 0
+ lui a2, 0
+ lui a3, 0
+ lui a4, 0
+ lui a5, 0
+ lui a6, 0
+ lui a7, 0
+
+ li t1, 0xffff
+1:
+
+ sw zero, 0(t0)
+ addi t0, t0, 4
+ and t0, t0, t1
+ bne t0, zero, 1b
+ lui t0, 0
+ lui t1, 0
+
+ la gp, _gp /* Initialize global pointer */
+ la sp, _fstack
+
+/* la t0, _fexception_stack
+ csrrw t0, mscratch, t0 */
+
+ /* clear the bss segment */
+ la t0, _fbss
+ la t1, _end
+1:
+#ifdef __riscv64
+ sd zero,0(t0)
+ addi t0, t0, 8
+#else
+ sw zero,0(t0)
+ addi t0, t0, 4
+
+#endif
+ bltu t0, t1, 1b
+ call main
+1:
+ j 1b
+
+ .data
+_recov_data: .long 0
diff --git a/software/bootldr/main.c b/software/bootldr/main.c
new file mode 100644
index 0000000000000000000000000000000000000000..bc3665b2c3384542dae33ae91a94657db67e3df8
--- /dev/null
+++ b/software/bootldr/main.c
@@ -0,0 +1,154 @@
+// TO DO: check integrity of the image before executing it
+
+
+#include <stdio.h>
+//#include <string.h>
+#include "riscv.h"
+
+#define IRAM_SIZE 65536
+#define LOADER_SIZE 512
+#define APP_IMAGE_TEXT 0x60000000
+#define APP_IMAGE_DATA 0x60020000
+#define LOADER_IMAGE 0x60012200
+
+#define print_line() print_char('\n');print_char('\r')
+
+typedef struct uart_reg {
+ uint32_t flags;
+ uint32_t buffer;
+} uart_reg;
+
+void __attribute__((__section__(".launcher_call"))) print_string (char * str, unsigned char len) {
+
+ for (char i=0; i < len; i++)
+ print_char(str[i]);
+
+
+}
+
+void __attribute__((always_inline)) print_char (char c) {
+ volatile uart_reg * uart_tx = (uart_reg *) 0x82000000;
+ while (!uart_tx->flags);
+ uart_tx->buffer = c;
+ uart_tx->flags = 2;
+
+}
+
+
+void __attribute__((__section__(".launcher_call"))) print_word (uint32_t word) {
+ int8_t i;
+ uint8_t disp;
+ uint32_t temp;
+ char c;
+
+ for (i=7; i >= 0; i--) {
+
+ disp = ((word >> (i<<2)) & 0xf);
+ if (disp <= 9 )
+ c = '0'+ disp;
+ else
+ c = 'A' + disp - 10;
+
+ print_char (c);
+ }
+
+}
+
+
+uint32_t __attribute__((__section__(".launcher_call"))) envm_read (uint32_t * addr) {
+
+ volatile uint32_t * wb_envm_dev = 0x87000000;
+
+ while (wb_envm_dev[0] & 0x1);
+ wb_envm_dev[1] = addr;
+ while (*wb_envm_dev & 0x1);
+
+ return wb_envm_dev[2];
+}
+
+
+void __attribute__((__section__(".launcher"))) iram_write (uint32_t * addr, uint32_t data) {
+
+ volatile uint32_t * wb_iram_dev = 0x87000010;
+
+
+ wb_iram_dev[0] = addr;
+ wb_iram_dev[1] = data;
+ asm ("nop");
+ // asm("nop");
+ // asm("nop");
+ // asm("nop");
+
+}
+
+
+
+
+void load_image ();
+
+
+void main(void)
+{
+
+
+ const char boot_logo [5] = {'b','o','o','t'};
+
+
+ volatile char * p_wd = 0x81000000;
+ void (*func)(void) = IRAM_SIZE - LOADER_SIZE + (&load_image - 0x200) ;
+ uint32_t i, data = 0;
+
+
+ //print_line();
+ print_string (boot_logo, 4);
+ print_line();
+
+
+
+ for (i=1024; i < (1<<16); i=i+4)
+ iram_write(i, 0);
+
+ for (i=0; i < 1024; i=i+4) {
+ data = envm_read (LOADER_IMAGE + i);
+ iram_write(IRAM_SIZE-LOADER_SIZE+i, data);
+ }
+
+ *p_wd = 1;
+
+ (*func)(); // jump to (relocated) load_image()
+
+
+
+ while(1);
+// *p_wd = 1; //watchdog
+
+
+
+}
+
+
+void __attribute__((__section__(".launcher"))) load_image () {
+ const char done [5] = {'D','o','n', 'e'};
+ uint32_t i, data = 0;
+ uint32_t * dram = 0;
+ void (*func)(void) = 0 ;
+
+ for (i=0; i < IRAM_SIZE-LOADER_SIZE; i=i+4) {
+ data = envm_read (APP_IMAGE_TEXT + i);
+ iram_write (i, data);
+ }
+
+ for (i=0; i < (1<<16)-1024; i=i+4) {
+ data = envm_read (APP_IMAGE_DATA + i);
+ *dram++ = data;
+ }
+ print_string(done, 4);
+
+
+ (*func)(); // run app
+
+ while(1);
+
+
+}
+
diff --git a/software/bootldr/riscv.h b/software/bootldr/riscv.h
new file mode 100644
index 0000000000000000000000000000000000000000..75d2ab9ef9274f111d9106b1797718e28e7c04e5
--- /dev/null
+++ b/software/bootldr/riscv.h
@@ -0,0 +1,37 @@
+#ifndef __RISCV_H
+#define __RISCV_H
+
+#ifdef __GNUC__
+
+#define riscv_read_csr(reg) ({ unsigned long __tmp; \
+ asm volatile ("csrr %0, " #reg : "=r"(__tmp)); \
+ __tmp; })
+
+#define riscv_write_csr(reg, val) \
+ asm volatile ("csrw " #reg ", %0" :: "r"(val))
+
+#define riscv_swap_csr(reg, val) ({ long __tmp; \
+ asm volatile ("csrrw %0, " #reg ", %1" : "=r"(__tmp) : "r"(val)); \
+ __tmp; })
+
+#define riscv_set_csr(reg, bit) ({ unsigned long __tmp; \
+ if (__builtin_constant_p(bit) && (bit) < 32) \
+ asm volatile ("csrrs %0, " #reg ", %1" : "=r"(__tmp) : "i"(bit)); \
+ else \
+ asm volatile ("csrrs %0, " #reg ", %1" : "=r"(__tmp) : "r"(bit)); \
+ __tmp; })
+
+#define riscv_clear_csr(reg, bit) ({ unsigned long __tmp; \
+ if (__builtin_constant_p(bit) && (bit) < 32) \
+ asm volatile ("csrrc %0, " #reg ", %1" : "=r"(__tmp) : "i"(bit)); \
+ else \
+ asm volatile ("csrrc %0, " #reg ", %1" : "=r"(__tmp) : "r"(bit)); \
+ __tmp; })
+
+#define riscv_rdtime() riscv_read_csr(time)
+#define riscv_rdcycle() riscv_read_csr(cycle)
+#define riscv_rdinstret() riscv_read_csr(instret)
+
+#endif
+
+#endif