For a sanity check I tried the same thing with my second DUE board - same problem: works with 1.5.6-R2, but not with 1.5.7.
The revisions.txt is the same as the release notes at http://arduino.cc/en/Main/ReleaseNotes
I can't see a likely culprit here:
ARDUINO 1.5.7 BETA - 2014.07.07
[core]
- Upgraded AVR toolchain: gcc 4.8.1, avr-libc 1.8.0
- Upgraded ARM toolchain: gcc 4.8.3-2014q1
- Upgraded avrdude to version 6.0.1
- ARM gcc doesn't require ia32-libs anymore on 64 bits linux systems
- avr: fixed typo in SerialEvent3 handling (Matthijs Kooijman)
- avr: HardwareSerial support for different size of TX and RX buffer sizes (Jan Baeyens)
- avr: HardwareSerial support for buffer sizes bigger than 256 bytes (Jan Baeyens)
- sam: Added configuration (parity, data bits, stop bits) to Serial1/2/3 of Arduino Due (bluesign2k)
- Removed a lot of compiler warnings from Arduino core
- avr: Fix EXTERNAL_NUM_INTERRUPTS for atmega128rfa1 and atmega256rfr2 (Matthijs Kooijman)
- sam: Fix to Wire::endTransmisson() return value (bluesign2k)
- sam: Fix to Wire usage of TWI status register (bluesign2k)
- avr: Fixed PROGMEM statements to be compatible with newer avr gcc (Scott Howard)
[ide]
- Moved to appbundler for building releases for MacOSX. (Haavar Valeur)
This should remove dependency from Java 1.6 on recent MacOSX. - Added support for '-' and '.' in filenames (Georg von Zengen)
- (re)Added 'arduino_debug.exe' in Windows build for debugging purposes
- Magic baudrate is no longer removed (it was a workaround for RXTX)
(for more info see github issues: #1203 and #995) - Allow overriding platform.txt using platform.local.txt (Matthijs Kooijman)
- Explicitly define compiler.path in avr/platform.txt (Matthijs Kooijman)
- Make the low available memory message a warning (Matt Robinson)
- Proceed with upload even if port can't be found (David Mellis)
- Added support for ArduinoISP
- Windows: added board detection on serial port menu
[libraries]
- Updated SpaceBrew library
- Fixed HttpClient::running() function
- Fixed HttpClient::ready() function (Manuel Rabade)
- Added HttpClient::noCheckSSL() method
- Improved speed of YunSerialTerminal
- Fixed CRC of shutdown command on YunSerialTerminal example
- Updates/Fix to various examples
- Added Wire.setClock(..) method (Kristian Sloth Lauszus)
The following changes are included also in the (not yet released) Arduino IDE 1.0.6:
[core]
- avr: Improved USB-CDC write speed (Justin Rajewski)
- avr: Improved USB-CDC read code (Paul Brook)
- avr: Fixed race condition in USB-CDC transmit (Paul Brook)
- Fixed wrong NULL pointer handling in Stream class (Amulya Kumar Sahoo)
- Added initVariant() hook to allow 3rd party variant-specific initialization
[ide]
- Fix toolchain command line to compile assembler files (Jimmy Hedman)
- If two libraries have the same header file use the lib with the same folder name (Paul Stoffregen)
[libraries]
- Robot_Control: removed duplicated SPI and Wire (Xun Yang)
- Robot_Control: fixed issue on motors being opposite (Xun Yang)
- Robot_Control: updated turning algorithm (Xun Yang)
- Esplora: added reading form Tinkerkit inputs
- SoftwareSerial: Fix idle level when initializing with inverted logic (Jens-Christian Skibakk)
[firmware]
- Wifishield: fixed paths on firmware upgrade scripts