HobbyTronics UNO PRO Board Definition does not work in newer IDE versions
Making your board definition work
What I did was slightly different from their directions, but:
Close any instances of the IDE you have running.
Create the directories along this path:
&lt;sketchbook&gt;/hardware/uno_pro/avr/variants/uno_pro

Where &lt;sketchbook&gt; refers to to where your IDE is saving sketches by default.
Place the following slightly modified boards.txt at &lt;sketchbook&gt;/hardware/uno_pro/avr/boards.txt:
uno_pro.name=Arduino Uno*Pro

uno_pro.upload.tool=avrdude
uno_pro.upload.protocol=arduino
uno_pro.upload.maximum_size=130048
uno_pro.upload.maximum_data_size=16384
uno_pro.upload.speed=115200

uno_pro.bootloader.tool=avrdude
uno_pro.bootloader.low_fuses=0xFF
uno_pro.bootloader.high_fuses=0xDE
uno_pro.bootloader.extended_fuses=0xFD
uno_pro.bootloader.unlock_bits=0x3F
uno_pro.bootloader.lock_bits=0x0F
uno_pro.bootloader.file=optiboot/optiboot_atmega1284p.hex

uno_pro.build.mcu=atmega1284p
uno_pro.build.f_cpu=16000000L
uno_pro.build.board=AVR_UNO_PRO
uno_pro.build.core=arduino:arduino
uno_pro.build.variant=uno_pro

This is the original file with one important modification, and that's the addition of arduino: in the second to last line reading uno_pro.build.core=arduino:arduino
Place the following (unmodified from original) pins_arduino.h at &lt;sketchbook&gt;/hardware/uno_pro/avr/variants/uno_pro/pins_arduino.h:
#ifndef Pins_Arduino_h
#define Pins_Arduino_h

#include &lt;avr/pgmspace.h&gt;

// ATMEL ATMEGA1284 on Hobbytronics UNO*Pro
//
//
// 2014-01-24 - Modified for Software Serial Library to work
//
//   ATMEGA1284 Pin     Arduino Mapping    Features
//     PA0                   D21  A7
//    PA1                   D20  A6
//     PA2                   D19  A5
//    PA3                   D18  A4   
//     PA4                   D17  A3            
//    PA5                   D16  A2    
//     PA6                   D15  A1 
//    PA7                   D14  A0
//
//     PB0                   D4
//    PB1                   D5
//     PB2                   D2
//    PB3                   D3               PWM
//     PB4                   D10                    PWM  SS
//    PB5                   D11                   MOSI
//     PB6                   D12              PWM  MISO
//    PB7                   D13              PWM  SCK
//
//     PC0                   D22                   SCL
//    PC1                   D23                   SDA
//     PC2                   D24              
//    PC3                   D25
//     PC4                   D26
//    PC5                   D27
//     PC6                   D28 
//    PC7                   D29
//
//     PD0                   D0                    RX
//    PD1                   D1                    TX
//     PD2                   D6                    RX1
//    PD3                   D7                    TX1
//     PD4                   D30              PWM
//    PD5                   D8               PWM
//     PD6                   D9               PWM
//    PD7                   D31              PWM
//

static const uint8_t SS   = 10;
static const uint8_t MOSI = 11;
static const uint8_t MISO = 12;
static const uint8_t SCK  = 13;

static const uint8_t SDA = 23;
static const uint8_t SCL = 22;
static const uint8_t LED = 13;

static const uint8_t A0 = 0;
static const uint8_t A1 = 1;
static const uint8_t A2 = 2;
static const uint8_t A3 = 3;
static const uint8_t A4 = 4;
static const uint8_t A5 = 5;
static const uint8_t A6 = 6;
static const uint8_t A7 = 7;

#define NUM_DIGITAL_PINS            32
#define NUM_ANALOG_INPUTS           8

// Macros
#define analogInputToDigitalPin(p)  ((p &lt; NUM_ANALOG_INPUTS) ? (p) + 14 : -1)
#define digitalPinToAnalogPin(p)    ((p) &gt;= 14 &amp;&amp; (p) &lt;= 21 ? (p) - 14 : -1 )
#define analogPinToChannel(p)         ((p) &lt; NUM_ANALOG_INPUTS ? NUM_ANALOG_INPUTS - (p) - 1: -1 )
#define digitalPinHasPWM(p)         ((p) == 3 || (p) == 8 || (p) == 9 || (p) == 10 || (p) == 12 || (p) == 13 || (p) == 30 || (p) == 31 )

#define ifpin(p,what,ifnot)     (((p) &gt;= 0 &amp;&amp; (p) &lt; NUM_DIGITAL_PINS) ? (what) : (ifnot))

extern const uint8_t digital_pin_to_pcint[NUM_DIGITAL_PINS];

#define digitalPinToPCICR(p)    ifpin(p,(&amp;PCICR),(uint8_t *)0)
#define digitalPinToPCICRbit(p) ifpin(p,(digital_pin_to_pcint[p] &gt;&gt; 3),0)
#define digitalPinToPCMSK(p)    (((p) &lt;= 1) ? (&amp;PCMSK3) : (((p) &lt;= 5) ? (&amp;PCMSK1) : (((p) &lt;= 9) ? (&amp;PCMSK3) : (((p) &lt;= 13) ? (&amp;PCMSK1) : (((p) &lt;= 21) ? (&amp;PCMSK0) : (((p) &lt;= 29) ? (&amp;PCMSK2) : (((p) &lt;= 31) ? (&amp;PCMSK3) : ((uint8_t *)0))))))))
#define digitalPinToPCMSKbit(p) ifpin(p,digital_pin_to_pcint[p] &amp; 0x7,0)

#define digitalPinToInterrupt(p)  ((p) == 6 ? 0 : ((p) == 7 ? 1 : ((p) == 2 ? 2 : NOT_AN_INTERRUPT)))

#ifdef ARDUINO_MAIN

#define PA 1
#define PB 2
#define PC 3
#define PD 4

const uint8_t digital_pin_to_pcint[NUM_DIGITAL_PINS] =
{
  24, // D0  PD0
  25, // D1  PD1 1
  10, // D2  PB2
  11, // D3  PB3
  8,  // D4  PB0
  9,  // D5  PB1 5
  26, // D6  PD2
  27, // D7  PD3  
  29, // D8  PD5
  30, // D9  PD6 9
  12, // D10 PB4
  13, // D11 PB5
  14, // D12 PB6
  15, // D13 PB7 13
  7,  // D14 PA7
  6,  // D15 PA6
  5,  // D16 PA5
  4,  // D17 PA4
  3,  // D18 PA3
  2,  // D19 PA2
  1,  // D20 PA1
  0,  // D21 PA0 21
  16, // D22 PC0
  17, // D23 PC1
  18, // D24 PC2
  19, // D25 PC3
  20, // D26 PC4
  21, // D27 PC5
  22, // D28 PC6
  23, // D29 PC7 29
  28, // D30 PD4
  31  // D31 PD7 31
};


// these arrays map port names (e.g. port B) to the
// appropriate addresses for various functions (e.g. reading
// and writing)
const uint16_t PROGMEM port_to_mode_PGM[] =
{
    NOT_A_PORT,
    (uint16_t) &amp;DDRA,
    (uint16_t) &amp;DDRB,
    (uint16_t) &amp;DDRC,
    (uint16_t) &amp;DDRD,
};

const uint16_t PROGMEM port_to_output_PGM[] =
{
    NOT_A_PORT,
    (uint16_t) &amp;PORTA,
    (uint16_t) &amp;PORTB,
    (uint16_t) &amp;PORTC,
    (uint16_t) &amp;PORTD,
};

const uint16_t PROGMEM port_to_input_PGM[] =
{
    NOT_A_PORT,
    (uint16_t) &amp;PINA,
    (uint16_t) &amp;PINB,
    (uint16_t) &amp;PINC,
    (uint16_t) &amp;PIND,
};

const uint8_t PROGMEM digital_pin_to_port_PGM[] =
{
  PD, // D0
  PD, // D1
  PB, // D2
  PB, // D3  
  PB, // D4
  PB, // D5
  PD, // D6
  PD, // D7
  PD, // D8
  PD, // D9
  PB, // D10
  PB, // D11
  PB, // D12
  PB, // D13
  PA, // D14
  PA, // D15
  PA, // D16
  PA, // D17
  PA, // D18
  PA, // D19
  PA, // D20
  PA, // D21
  PC, // D22
  PC, // D23
  PC, // D24
  PC, // D25
  PC, // D26
  PC, // D27
  PC, // D28
  PC, // D29
  PD, // D30
  PD, // D31
};

const uint8_t PROGMEM digital_pin_to_bit_mask_PGM[] =
{
  _BV(0), // D0  PD0
  _BV(1), // D1  PD1
  _BV(2), // D2  PB2
  _BV(3), // D3  PB3
  _BV(0), // D4  PB0
  _BV(1), // D5  PB1
  _BV(2), // D6  PD2
  _BV(3), // D7  PD3  
  _BV(5), // D8  PD5
  _BV(6), // D9  PD6
  _BV(4), // D10 PB4
  _BV(5), // D11 PB5
  _BV(6), // D12 PB6
  _BV(7), // D13 PB7
  _BV(7), // D14 PA7 (A0)
  _BV(6), // D15 PA6 (A1)
  _BV(5), // D16 PA5 (A2)
  _BV(4), // D17 PA4 (A3)
  _BV(3), // D18 PA3 (A4)
  _BV(2), // D19 PA2 (A5)
  _BV(1), // D20 PA1 (A6)
  _BV(0), // D21 PA0 (A7)
  _BV(0), // D22 PC0
  _BV(1), // D23 PC1
  _BV(2), // D24 PC2
  _BV(3), // D25 PC3
  _BV(4), // D26 PC4
  _BV(5), // D27 PC5
  _BV(6), // D28 PC6
  _BV(7), // D29 PC7
  _BV(4), // D30 PD4
  _BV(7), // D31 PD7
};

const uint8_t PROGMEM digital_pin_to_timer_PGM[] =
{
  NOT_ON_TIMER, // D0  PD0
  NOT_ON_TIMER, // D1  PD1
  NOT_ON_TIMER, // D3  PB2
  TIMER0A,      // D3  PB3
  NOT_ON_TIMER, // D4  PB0
  NOT_ON_TIMER, // D5  PB1
  NOT_ON_TIMER, // D6  PD2
  NOT_ON_TIMER, // D7  PD3  
  TIMER1A,      // D8  PD5
  TIMER2B,      // D9  PD6
  TIMER0B,      // D10 PB4
  NOT_ON_TIMER, // D11 PB5
  TIMER3A,      // D12 PB6
  TIMER3B,      // D13 PB7
  NOT_ON_TIMER, // D14 PA0
  NOT_ON_TIMER, // D15 PA1
  NOT_ON_TIMER, // D16 PA2
  NOT_ON_TIMER, // D17 PA3
  NOT_ON_TIMER, // D18 PA4
  NOT_ON_TIMER, // D19 PA5
  NOT_ON_TIMER, // D20 PA6
  NOT_ON_TIMER, // D21 PA7
  NOT_ON_TIMER, // D22 PC0
  NOT_ON_TIMER, // D23 PC1
  NOT_ON_TIMER, // D24 PC2
  NOT_ON_TIMER, // D25 PC3
  NOT_ON_TIMER, // D26 PC4
  NOT_ON_TIMER, // D27 PC5
  NOT_ON_TIMER, // D28 PC6
  NOT_ON_TIMER, // D29 PC7
  TIMER1B,      // D30 PD4
  TIMER2A,      // D31 PD7
};


#endif // ARDUINO_MAIN

#endif // Pins_Arduino_h
// vim:ai:cin:sts=2 sw=2 ft=cpp

Open the IDE and your board should be listed.  It should compile with a blank sketch.  I did not test further than that.
MCUDude MightyCore
Your board could also likely be made to work with MCUdude MightyCore.  However, MightyCore will not have your pin mapping.  So, although you could use it, you would need to ignore the normal UNO pin labeling and instead of work out which pin number used by the chosen MightyCore variant routes to which pin on the UNO headers.  It would be annoying to do, but you could do that by comparing entries in your adapter's pins_arduino.h file with the entries in the chosen variant from the MightCore package.  But, the modifications above seem to work fine.  So, I don't necessarily suggest that route; I'm just saying it could be used that way also.
MightyCore could also be modified, but that works out to the same or more work than just using your board definition, I think.