Raspberry Pi Pico MIDI controller with SamplerBox 2019 image PiZero

Hi Rajiv,
Thanks, I like exchanging ideas.
Regarding the PiZero, concluding the issue is solved by agreeing that the 2020 image is incompatible is unsatisfying for next reasons:

1. the OS is the same (dedicated setup based on debian Jessie).
   I may have done and rpi-update - but this should enlarge compatibility instead of reducing it.
   
2. The hardware should not react on application changes.
   
3. I accept "it doesn't work", but can't understand "it doesn't boot".
   I'd sure would like to know what startup messages say when powering on with screen & keyboard attached (if possible).
   I suspect the PI is started and perhaps you can even logon via network, if enabled in your case, so the direct screen/keyboard isn't even necessary.
   

There is no apparent reason why the 2020 image should have become incompatible, leading to a more alarming statement: no reason to think next image should be compatible again as it's a next application change on the same outdated Jessie base - leaving you empty handed again. Hmm.
I am working on a less limited, buster based, image in order to support PI-4 (got the prototype working) and others like PiZero (when  I started I wasn't aware of anybody using the zero already). But I expect the distributable version will take several months, realistic before yearend earliest.

If you want work with Pico and 2019 release, you can apply the patch yourself: around line 940 in samplerbox.py replace

Code:

    gv.samplesdir = SAMPLES_ONUSB if os.listdir(SAMPLES_ONUSB) else SAMPLES_INBOX      # use builtin folder (containing 0 Saw) if no user media containing samples has been found
    #gv.basename = next((f for f in os.listdir(gv.samplesdir) if f.startswith("%d " % gv.PRESET)), None)      # or next(glob.iglob("blah*"), None)

with

Code:

    gv.samplesdir = gv.SAMPLES_INBOX
    try:
        if os.listdir(gv.SAMPLES_ONUSB):
            for f in os.listdir(gv.SAMPLES_ONUSB):
                if re.match(r'[0-9]* .*', f):
                    if os.path.isdir(os.path.join(gv.SAMPLES_ONUSB,f)):
                        gv.samplesdir = gv.SAMPLES_ONUSB
                        break
            if gv.samplesdir == gv.SAMPLES_INBOX:
                print ("USB device on %s has no samplesets, using SD space on %s" %(gv.SAMPLES_ONUSB, gv.SAMPLES_INBOX) )
    except:
        print ("Error reading USB device mounted on %s" %gv.SAMPLES_ONUSB)

If you copy/paste the code, the confusing line wrapping is gone...

Hope this helps,
Hans