Archiv für den Monat: August 2021

Linux Repair GRUB2 on EFI System

Update: fixed (in Windows no GUI start in msconfig auswählen)!

Da hatte ich einen Riesenschreck bekommen – von einem Tag auf den andern bootet Ubuntu nicht mehr!

Die Fehlermeldung ist reichlich obskur – Failed to open \EFI\UBUNTU\ und dann seltsame Symbole. Da ist wohl im BIOS was durcheinander geraten.

Windows konnte zum Glück noch starten.

Jedenfalls hab ich es nicht mit einfachen Mitteln (boot-repair etc) hingekriegt.

Hier die Lösung von

Hole den Ubuntu-Live-USB-Stick und boote ihn (über UEFI natürlich).

Starte „Try Ubuntu“ und öffne dann ein Terminal.

Mit fdisk -l lassen sich schnell und unkompliziert die Partitionen finden.

sudo fdisk -l

sudo mount /dev/nvme1n1p4 /mnt
sudo mount /dev/nvme0n1p1 /mnt/boot/efi
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
sudo chroot /mnt
grub-install /dev/nvme0n1p1

nvme0n1p1 ist die EFI-Systempartition.

nvme1n1p4 ist mein Ubuntu Ext4.


Nach Windows-Boot kehrt das Problem zurück!

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RC Car Speedometer

Basierend auf einem TTGO LoRa mit OLED 128×64 mit BN-880 GPS.


  • Batterie/Lipo an den unteren Bat-Connector
  • GPS an 5V/12(RX)/13(TX)/GND

Arduino mit der ESP32-Erweiterung, Board TTGO-LoRa-OLED.


  • 5 Hz GPS-Datenrate
  • Die 5 höchsten Geschwindigkeiten, die höchste extra groß angezeigt
  • Satellitenanzahl-Anzeige

Hier der Code:

//Libraries for OLED Display
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

const unsigned char ubxRate1Hz[]  = 
  { 0x06,0x08,0x06,0x00,0xE8,0x03,0x01,0x00,0x01,0x00 };
const unsigned char ubxRate5Hz[]  =
  { 0x06,0x08,0x06,0x00,200,0x00,0x01,0x00,0x01,0x00 };
const unsigned char ubxRate10Hz[]  =
  { 0x06,0x08,0x06,0x00,100,0x00,0x01,0x00,0x01,0x00 };
const unsigned char ubxRate16Hz[]  =
  { 0x06,0x08,0x06,0x00,50,0x00,0x01,0x00,0x01,0x00 };

// Disable specific NMEA sentences
const unsigned char ubxDisableGGA[]  =
  { 0x06,0x01,0x08,0x00,0xF0,0x00,0x00,0x00,0x00,0x00,0x00,0x01 };
const unsigned char ubxDisableGLL[]  =
  { 0x06,0x01,0x08,0x00,0xF0,0x01,0x00,0x00,0x00,0x00,0x00,0x01 };
const unsigned char ubxDisableGSA[]  =
  { 0x06,0x01,0x08,0x00,0xF0,0x02,0x00,0x00,0x00,0x00,0x00,0x01 };
const unsigned char ubxDisableGSV[]  =
  { 0x06,0x01,0x08 

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,0x00,0xF0,0x03,0x00,0x00,0x00,0x00,0x00,0x01 }; const unsigned char ubxDisableRMC[] = { 0x06,0x01,0x08,0x00,0xF0,0x04,0x00,0x00,0x00,0x00,0x00,0x01 }; const unsigned char ubxDisableVTG[] = { 0x06,0x01,0x08,0x00,0xF0,0x05,0x00,0x00,0x00,0x00,0x00,0x01 }; const unsigned char ubxDisableZDA[] = { 0x06,0x01,0x08,0x00,0xF0,0x08,0x00,0x00,0x00,0x00,0x00,0x01 }; #define Battadc 34 //OLED pins #define OLED_SDA 4 #define OLED_SCL 15 #define OLED_RST 16 #define SCREEN_WIDTH 128 // OLED display width, in pixels #define SCREEN_HEIGHT 64 // OLED display height, in pixels #define SDA 21 #define SCL 22 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RST); bool enable_dbg; bool sig_valid, sig_rxok; float sig_speed, saved_spd; int sig_sats; float maxspeed[5]; // Cut out the wanted substring from a comma-separated string static String extract_val(char *buf, int len, int cpos) { String str=""; int i,cc=0,cs=0,ce=255; for (i=0;i 0) sig_valid = true; Serial.println(s); sig_speed = s.toFloat(); saved_spd = sig_speed; } else if (buf[2]=='G' && buf[3]=='G' && buf[4]=='A') { display.print(buf); String s = extract_val(buf, pos, 7); Serial.println(s); sig_sats = s.toInt(); } } else if (c=='$') pos=0; else if (pos < sizeof(buf)) buf[pos++] = c; } //Warteschleife, die ankommende Daten vom GPS Modul verarbeitet und den Status des Tasters prüft static void smartdelay(unsigned long ms) { unsigned long start = millis(); do { while (Serial2.available()) { char; parse_gps(c); if (enable_dbg) Serial.print(c); //display.print(c); } //display.display(); } while (millis() - start < ms); } static void sendUBX( const unsigned char *progmemBytes, size_t len ) { Serial2.write( 0xB5 ); // SYNC1 Serial2.write( 0x62 ); // SYNC2 uint8_t a = 0, b = 0; while (len-- > 0) { uint8_t c = ( *progmemBytes++ ); a += c; b += a; Serial2.write( c ); } Serial2.write( a ); // CHECKSUM A Serial2.write( b ); // CHECKSUM B delay(100); } static void updateRate() { sendUBX(ubxRate5Hz, 10); } void setup() { pinMode(0, INPUT_PULLUP); // button pinMode(SCL, INPUT_PULLUP); // I2C of GPS compass pinMode(SDA, INPUT_PULLUP); analogSetAttenuation(ADC_0db); // control sensitivity; ADC_11db, ADC_6db, ADC_2_5db, ADC_0db pinMode(Battadc, INPUT); adcAttachPin(Battadc); Serial.begin(115200); // debug Serial2.begin(9600,SERIAL_8N1,12,13); // GPS //reset OLED display via software pinMode(OLED_RST, OUTPUT); digitalWrite(OLED_RST, LOW); delay(20); digitalWrite(OLED_RST, HIGH); //initialize OLED Wire.begin(OLED_SDA, OLED_SCL); if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3c, false, false)) { // Address 0x3C for 128x32 //Serial.println(F("SSD1306 allocation failed")); for(;;); // Don't proceed, loop forever } display.setTextColor(WHITE); display.setTextSize(1); display.clearDisplay(); display.display(); delay(2000); sendUBX(ubxDisableGLL, 12); sendUBX(ubxDisableGSA, 12); sendUBX(ubxDisableGSV, 12); sendUBX(ubxDisableRMC, 12); sendUBX(ubxDisableZDA, 12); Serial2.print("$PUBX,41,1,0007,0003,19200,0*25\r\n"); Serial2.flush(); delay(100); Serial2.end(); Serial2.begin(19200,SERIAL_8N1,12,13); delay(1000); updateRate(); } void loop() { int i; bool spdwritten = false; char tmp[32]; float spd; smartdelay(0); display.clearDisplay(); // drawString(x,y,text);? or ACROBOTIC_SSD1306 with setTextXY/putString display.setCursor(0, 0); if (sig_valid) { spd = sig_speed; sig_speed = 0.0; // show maximum speed, with 5 places to see glitches display.println("Geschwindigkeit (max)"); for (i=0; i<5; i++) { if (spd > maxspeed[i] && !spdwritten) { maxspeed[i] = spd; spdwritten = true; break; } } for (i=0; i<5; i++) { if (i==0) display.setTextSize(2); sprintf(tmp, "%4.1f km/h", maxspeed[i]); display.println(tmp); if (i==0) display.setTextSize(1); } // show current speed sprintf(tmp,"S%4.1f Sats %3d", saved_spd, sig_sats); display.print(tmp); } else { display.println("No GPS fix."); if (sig_rxok) display.println("GPS RX ok"); sprintf(tmp," Sats %3d", sig_sats); display.print(tmp); } display.display(); int vbatt = analogRead(Battadc); if (digitalRead(0)==0) { // clear for (i=0;i<5; i++) maxspeed[i] = 0.0; display.clearDisplay(); } }