Flashing error
Hello, I get this error when trying flashing my prusa i3 mk3s. "ERROR: No valid record found in Intel Hex file"
That version number is what the printer identifies itself as in the display when the printer is on.
I am trying to flash with the file from https://help.prusa3d.com/downloads/mk3s. It is extracted and I am targeting the .HEX file. The printer is on, the cable is connected. I tried rebooting the pc and printer but no luck.
What is going wrong here?
I was a bit unsure about the version number of the printer, because I got it second hand and it was upgraded with some MMU stuff, but it was later removed, so it doesn't always match the images for identifying version, but I assumed I can rely on the printer's self report.
Here is the error report in full:
avrdude-slic3r -v -p atmega2560 -c wiring -P COM7 -b 115200 -D -U flash:w:0:C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex:i
avrdude-slic3r: Version 6.3-20160220-prusa3d, compiled on Nov 6 2025 at 10:47:10
Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
Copyright (c) 2007-2014 Joerg Wunsch
Using Port : COM7
Using Programmer : wiring
Overriding Baud Rate : 115200
AVR Part : ATmega2560
Chip Erase delay : 9000 us
PAGEL : PD7
BS2 : PA0
RESET disposition : dedicated
RETRY pulse : SCK
serial program mode : yes
parallel program mode : yes
Timeout : 200
StabDelay : 100
CmdexeDelay : 25
SyncLoops : 32
ByteDelay : 0
PollIndex : 3
PollValue : 0x53
Memory Detail :
Block Poll Page Polled
Memory Type Mode Delay Size Indx Paged Size Size #Pages MinW MaxW ReadBack
----------- ---- ----- ----- ---- ------ ------ ---- ------ ----- ----- ---------
eeprom 65 10 8 0 no 4096 8 0 9000 9000 0x00 0x00
flash 65 10 256 0 yes 262144 256 1024 4500 4500 0x00 0x00
lfuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00
hfuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00
efuse 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00
lock 0 0 0 0 no 1 0 0 9000 9000 0x00 0x00
calibration 0 0 0 0 no 1 0 0 0 0 0x00 0x00
signature 0 0 0 0 no 3 0 0 0 0 0x00 0x00
Programmer Type : Wiring
Description : Wiring
Programmer Model: AVRISP
Hardware Version: 15
Firmware Version Master : 2.10
Vtarget : 0.0 V
SCK period : 0.1 us
avrdude-slic3r: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.01s
avrdude-slic3r: Device signature = 0x1e9801 (probably m2560)
avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: reading input file "C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex"
avrdude-slic3r: ERROR: No valid record found in Intel Hex file "C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex"
avrdude-slic3r: read from file 'C:\Users\speed\Downloads\__MACOSX\prusa3d_fw_3_14_1_MK3S\._MK3S_MK3S+_FW_3.14.1_MULTILANG.hex' failed
avrdude-slic3r: safemode: hfuse reads as D0
avrdude-slic3r: safemode: efuse reads as FD
avrdude-slic3r: safemode: Fuses OK (E:FD, H:D0, L:FF)
avrdude-slic3r done. Thank you.
You *might* have a corrupt file so download again but this time first do a factory reset to clear out any legacy settings that could confuse the issue.
https://help.prusa3d.com/article/factory-reset-mk2s-mk2-5s-mk3s_2216
Cheerio,
RE: Flashing error
I have tried redownloading the file, same issue. Since this printer I believe may have started as a mk3 converted to an MK3S printer, it has upgrades applied to it regarding "auto bed level and filament registrering to extruder", the previous owner mentioned an upgrade from mmu2 to mmu2s. (it doesn't have MMU now), He also said he "ran octoprint on it" . I am worried if I factory reset it I will make it no longer work.
The reset is safe - you will then need to flash the MK3s firmware to make it fully usable - for full peace of mind I would run through all the checks and configurations that are normally the completion of the kit-build process:
https://help.prusa3d.com/guide/9-preflight-check_36224#36232
And if you hit difficulties, as long as this is a genuine Prusa printer and not a Chinese clone, Prusa Support will help via chat.
It may also help to read: https://help.prusa3d.com/article/firmware-updating-issues-mk2-5s-mk3s-mmu2s-mmu3_2225
Cheerio,