//+============================================================================ ========================================
// Select font
// A full list of u8g2 fonts can be found here:
//    https://github.com/olikraus/u8g2/wiki/fntlistall
// ...and here are the ones available in FZ (currently: all of them):
//    grep -P '.*u8g2.*\[[0-9]*\]' lib/u8g2/u8g2_fonts.c | sed 's/.*\(u8g2_.*\)\[.*/\1/'
//
#if 0  //! Extra fonts is just too memory hungry
#include <u8g2.h>
void  setFont (Canvas* const canvas, const uint8_t* font)
{
	u8g2_SetFontMode(&canvas->fb, 1);  // no idea - but canvas.c does it <shrug>
	u8g2_SetFont(&canvas->fb, font);
}
#endif

litui : @BlueChip for posterity, the function to break at is flipper_application_spawn. At that point, you can set new breakpoints in your fap code and continue.

/*

This is wrong on quite a few levels!
https://training.ti.com/introduction-i2c-reserved-addresses

void  doit (void)
{
    furi_hal_i2c_acquire(&furi_hal_i2c_handle_external);
    printf("Scanning external i2c on PC0(SCL)/PC1(SDA)\r\n"
           "Clock: 100khz, 7bit address\r\n"
           "\r\n");
    printf("  | 0 1 2 3 4 5 6 7 8 9 A B C D E F\r\n");
    printf("--+--------------------------------\r\n");
    for(uint8_t row = 0; row < 0x8; row++) {
        printf("%x | ", row);
        for(uint8_t column = 0; column <= 0xF; column++) {
            bool ret = furi_hal_i2c_is_device_ready(
                &furi_hal_i2c_handle_external, ((row << 4) + column) << 1, 2);
            printf("%c ", ret ? '#' : '-');
        }
        printf("\r\n");
    }
    furi_hal_i2c_release(&furi_hal_i2c_handle_external);
}
*/


region locking : firmware/targets/f7/furi_hal/furi_hal_region.c


#			if 0  //! scrolling works beautifully, but the LCD refresh can't keep up :(
			// Waveform
			if (cnt) {  // start
				for (int a = ACC_1;  a < ACC_N;  a++) {
					canvas_draw_dot(canvas, x,y[a]+v[a][idx]);
					for (int i = 1;  i < aw -cnt;  i++) {
						canvas_draw_line(canvas, x+i,y[a]+v[a][i-1] , x+i,y[a]+v[a][i]);
					}
				}
			} else {    // scroll
				for (int a = ACC_1;  a < ACC_N;  a++) {
					for (int i = 0;  i < aw;  i++) {
						int  off  = (idx +i) %aw;
						int  prev = off ? off-1 : aw-1;
						canvas_draw_line(canvas, x+i,y[a]+v[a][prev] , x+i,y[a]+v[a][off]);
					}
				}
			}

#			else
			int  end = idx ? idx : aw;
			for (int a = ACC_1;  a < ACC_N;  a++) {
				canvas_draw_dot(canvas, x,y[a]+v[a][idx]);
				if (state->apause) {
					for (int i = 1;  i < end;  i++)
						canvas_draw_line(canvas, x+i,y[a]+v[a][i-1] , x+i,y[a]+v[a][i]);
				} else {
					for (int i = 1;  i < end;  i++)
						canvas_draw_line(canvas, x+i,y[a]+v[a][i-1] , x+i,y[a]+v[a][i]);
					for (int i = end+10;  i < aw -cnt;  i++)
						canvas_draw_line(canvas, x+i,y[a]+v[a][i-1] , x+i,y[a]+v[a][i]);
				}
			}

			// Wipe bar
			if (end   < aw)  canvas_draw_line(canvas, x+end,y[0], x+end,y[2]+ah-1);
			if (++end < aw)  canvas_draw_line(canvas, x+end,y[0], x+end,y[2]+ah-1);
			if (++end < aw)  canvas_draw_line(canvas, x+end,y[0], x+end,y[2]+ah-1);
#			endif