Flashing Espruino fails, bootoader LED not pulsating

Hy, I received my 2 Espruinos yesterday. After firing on of them up, I realized that it still had a slightly old firmware on it with that regression bug where some characters after each function have to be inserted to make it work.

Now i tried to upgrade the 2 espruinos (via the chrome IDE as explained in the guide), it worked like a charm for the first device.
When i tried to do it with the second one, i realized that the bootloader LED wasn't pulsating as described (and as my first device did). Instead the blue & red (LED1&3) are both lighting up very bright and staying that way until i press the reset button again. I first thought this had sth to do with my windows laptop. The device also isn't recognized as a serial device anymore when it is in this state.

Now i tried it on my linux laptop with the same result. Here is the syslog output i get (first doing a normal reset and then the btn+reset reset for the bootloader)

# reset espruino normally
Jan 30 19:48:18 paulbook3 kernel: [ 1028.760404] usb 2-1.2: new full-speed USB device number 37 using ehci-pci
Jan 30 19:48:18 paulbook3 kernel: [ 1028.855671] usb 2-1.2: New USB device found, idVendor=0483, idProduct=5740
Jan 30 19:48:18 paulbook3 kernel: [ 1028.855687] usb 2-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jan 30 19:48:18 paulbook3 kernel: [ 1028.855696] usb 2-1.2: Product: STM32 Virtual COM Port  
Jan 30 19:48:18 paulbook3 kernel: [ 1028.855704] usb 2-1.2: Manufacturer: STMicroelectronics
Jan 30 19:48:18 paulbook3 kernel: [ 1028.855712] usb 2-1.2: SerialNumber: 48E074533330
Jan 30 19:48:18 paulbook3 kernel: [ 1028.857526] cdc_acm 2-1.2:1.0: This device cannot do calls on its own. It is not a modem.
Jan 30 19:48:18 paulbook3 kernel: [ 1028.857635] cdc_acm 2-1.2:1.0: ttyACM0: USB ACM device
Jan 30 19:48:18 paulbook3 mtp-probe: checking bus 2, device 37: "/sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2"
Jan 30 19:48:18 paulbook3 mtp-probe: bus: 2, device: 37 was not an MTP device

# try to put device into bootloader mode
Jan 30 19:48:22 paulbook3 kernel: [ 1033.426277] usb 2-1.2: USB disconnect, device number 37
Jan 30 19:48:23 paulbook3 kernel: [ 1033.626612] usb 2-1.2: new full-speed USB device number 38 using ehci-pci
Jan 30 19:48:23 paulbook3 kernel: [ 1033.698622] usb 2-1.2: device descriptor read/64, error -32
Jan 30 19:48:23 paulbook3 kernel: [ 1033.874694] usb 2-1.2: device descriptor read/64, error -32
Jan 30 19:48:23 paulbook3 kernel: [ 1034.050810] usb 2-1.2: new full-speed USB device number 39 using ehci-pci
Jan 30 19:48:23 paulbook3 kernel: [ 1034.122837] usb 2-1.2: device descriptor read/64, error -32
Jan 30 19:48:23 paulbook3 kernel: [ 1034.298915] usb 2-1.2: device descriptor read/64, error -32
Jan 30 19:48:24 paulbook3 kernel: [ 1034.474971] usb 2-1.2: new full-speed USB device number 40 using ehci-pci
Jan 30 19:48:24 paulbook3 whoopsie[1076]: online
Jan 30 19:48:24 paulbook3 kernel: [ 1034.883016] usb 2-1.2: device not accepting address 40, error -32
Jan 30 19:48:24 paulbook3 kernel: [ 1034.955220] usb 2-1.2: new full-speed USB device number 41 using ehci-pci
Jan 30 19:48:24 paulbook3 kernel: [ 1035.363240] usb 2-1.2: device not accepting address 41, error -32
Jan 30 19:48:24 paulbook3 kernel: [ 1035.363408] hub 2-1:1.0: unable to enumerate USB device on port 2
Jan 30 19:48:25 paulbook3 whoopsie[1076]: online

Is this a known problem? How can I update that second device?