make ATTINY85 with RS485 retun error

[expertup]

While I run command:
make attiny85 RS485=B2 LED_START_FLASHES=0 TIMEOUT=8 BAUD_RATE=19200 NO_START_APP_ON_POR=1 START_APP_ON_EXTR=1
return this error:

avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=attiny85 -DF_CPU=8000000L  -DBAUD_RATE=19200 '-DLED_START_FLASHES=0'           -DWDTTIME=8 -DNO_START_APP_ON_POR=1 -DSTART_APP_ON_EXTR=1 -DRS485=B2 '-DVIRTUAL_BOOT_PARTITION' '-DSOFT_UART' -Wl,-Tlink_optiboot.ld -Wl,--relax -nostartfiles -o optiboot_attiny85.elf optiboot.o
c:/users/dell/programs/avr8-gnu-toolchain/bin/../lib/gcc/avr/12.1.0/../../../../avr/bin/ld.exe: optiboot_attiny85.elf section `.text' will not fit in region `text'
c:/users/dell/programs/avr8-gnu-toolchain/bin/../lib/gcc/avr/12.1.0/../../../../avr/bin/ld.exe: section .version LMA [0000000000001ffe,0000000000001fff] overlaps section .text LMA [0000000000001dc0,0000000000002005]
c:/users/dell/programs/avr8-gnu-toolchain/bin/../lib/gcc/avr/12.1.0/../../../../avr/bin/ld.exe: region `text' overflowed by 0 bytes
collect2.exe: error: ld returned 1 exit status
make: *** [optiboot_attiny85.elf] B▒▒d 1
rm optiboot.o

But if I run without RS485=B2 pogram is compling.

I tried to add attiny85: LDSECTIONS = -Wl,--section-start=.text=0x1c00 in Makefile.tiny but problem is after connect attiny85 to power, the microcontroller runs the main program without the bootloader. This is do after writ 1st time programvia bootloader. In the project I need to disable the reset pin and use it as an additional pin. So the bootloader must start after attiny85 is powered up.

[WestfW]

Try an older version of gcc. The latest Microchip version is avr-gcc 5.4.something, and Arduino is support 7.3.something.
12.1.0 is WAY "out there", and I'm not inclined to spend time analyzing/debugging/fixing optiboot to work with it. It's disappointing that it apparently causes code size to grow so much - it's 568 bytes with v5.4 (Hmm. Ok, it's not THAT much bigger - the allocated size turns out to be 576 bytes...)

Note that the mechanism for specifiying bootloader size and start address has changed recently, so that it's now in the C code instead of being controlled by section-start linker commands. See the optiboot.c code near "sectionOpts()" -just bump up VBSIZE...

[mcuee]

FYI, latest Atmel toolchain is now based on avr-gcc 7.3.
https://www.microchip.com/en-us/tools-resources/develop/microchip-studio/gcc-compilers

The older avr-gcc 5.4 based version is still available though.

[mcuee]

Interestingly urboot only recommends avr-gcc 4.8.1 and avr-gcc 5.4 now.

But I think later avr-gcc 7.3 based toolchain will be used for UPDI parts support.

[mcuee]

As of now, Arduino shiped toolchain works with optiboot/optiboot_x.

For optiboot_dx, you may want to use the toolchain from DxCore. It also works with optiboot/optiboot_dx.
avrdudes/avrdude#1200 (comment)

You can also use Atmel toolchain as the base and manually copy the necessary files from the DFPs from Atmel Studio but that is a hassle.

[mcuee]

I have tested with Atmel toolchain (avr-gcc 7.3 based) and there is no ssue to build the bootloader.

FYI, MSYS2 comes with avr-gcc 8.5 and it seems to work as well.

$ make attiny85 RS485=B2 LED_START_FLASHES=0 TIMEOUT=8 BAUD_RATE=19200 NO_START_APP_ON_POR=1 START_APP_ON_EXTR=1
avr-gcc.exe (GCC) 8.5.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BAUD RATE CHECK: Desired: 19200, Real: 19230, UBRRL = 51, Difference=0.1%
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=attiny85 -DF_CPU=8000000L  -DBAUD_RATE=19200 '-DLED_START_FLASHES=0'           -DWDTTIME=8 -DNO_START_APP_ON_POR=1 -DSTART_APP_ON_EXTR=1 -DRS485=B2 '-DVIRTUAL_BOOT_PARTITION' '-DSOFT_UART'   -c -o optiboot.o optiboot.c
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=attiny85 -DF_CPU=8000000L  -DBAUD_RATE=19200 '-DLED_START_FLASHES=0'           -DWDTTIME=8 -DNO_START_APP_ON_POR=1 -DSTART_APP_ON_EXTR=1 -DRS485=B2 '-DVIRTUAL_BOOT_PARTITION' '-DSOFT_UART' -Wl,-Tlink_optiboot.ld -Wl,--relax -nostartfiles -o optiboot_attiny85.elf optiboot.o
avr-size optiboot_attiny85.elf
   text    data     bss     dec     hex filename
    576       0       0     576     240 optiboot_attiny85.elf
avr-objcopy -j .text -j .data -j .version --set-section-flags .version=alloc,load -O ihex optiboot_attiny85.elf optiboot_attiny85.hex
avr-objdump -h -S optiboot_attiny85.elf > optiboot_attiny85.lst
rm optiboot.o

[mcuee]

I guess this issue can be closed.