picowota does not seem to work with pico-sdk 2.0.0

[bobstaff147]

I used picowota very successfully about a year ago prior to the release of pico-sdk 2.0.0 and it worked well.

I've just started a new project using pico-sdk 2.0.0 and could not get it to work. On several occasions my picow got into a state where I could not load new versions of my application via usb, I could recover the picow using flash_nuke.

When I tried to load code using serial_flash I'd get this message

image load address too low

It seemed to be trying to load the application at the base of the flash area. 0x10000000.

Eventually I thought to revert to sdk 1.5.1 and it now works fine.

Do you have any thoughts on what the issue might be?

[usedbytes]

Thanks for the report. My best guess is something changed related to the linker script

I’ll try and find some time to reproduce your issue. Does it reproduce with the “picowota-blink” example?

edit: Oh… but you seem to be saying it’s intermittent or non-deterministic? Maybe something changed in the network stack and I have a bug in the packet handler. If that were the case I’d expect the “seal” stage to fail though.

[bobstaff147]

Yes it is repeatable with the picowota-blink example.

It was a little confusing, it seemed that with larger apps ~700kB the picow would get in a state where I'd have to nuke the flash.

With smaller apps I could not load new apps and would get the error from serial-flash

I've had a cursory look at what the code is using from the SDK in terms of memory layout and not yet found anything that has changed in SDK 2.0.0

Thanks for looking at it, I'll keep digging also

[bobstaff147]

It seems if I load picowota built with 1.5.1 I can then use it to load apps built with 2.0.0

Looking at the elf files it seems that with 2.0.0 the .debug_info section of the blink program has grown dramatically from 0xa0d bytes (in 1.5.1) to 0x3efe5 bytes. I'll look at disabling debug info I had not explicitly enabled it in either build

[Stubblet]

Looking at this would seem to support the hypothesis that the layout has changed:

D:\git\VSCode-Progamming\ntp_clock>serial-flash tcp:192.168.254.150:4242 build\oledClock.elf
Error: loading ELF build\oledClock.elf: unexpected read from SHT_NOBITS section

This is a 1.5M file (the uf2 is only 760k)

[czoltan1026]

I haven't tried pico sdk 1.5.1, but with 2.0.0 this only occurs for me when I try to serial-flash a binary that has been built by using picowota_build_combined.
Flashing picowota bootloader then serial-flash the plain old elf that was created by cmake works fine everytime

1. flash cominbed -> fail
2. flash plain old elf -> success
3. wait until program I hacked together go back to picowota boot, then flash plain old elf -> success
4. try to flash combined again -> fail