Memory corruption when using serial protocol

[acbits]

Describe the bug
Memory entries are missing when using the serial protocol.

To Reproduce
Run the attached script as
ats-mini-upload stations.txt /dev/ttyACM0

Expected behavior
All uploaded entries should be visible in the memory.

Information:
https://github.com/esp32-si4732/ats-mini/actions/runs/25708614885

Additional context

The errors are not always happening and not at the same memory locations.

[acbits]

ats-mini-upload script

#!/bin/bash

# Unix script to send memory entries to the ATS Mini.
# The entries are sorted by group, frequency in ascending order.
MAX_ENTRIES=99
STATIONS="$1"
PORT=${2:-'/dev/ttyACM0'}
DELIM='|'

if [[ ! -f "$STATIONS" || ! -c $PORT ]]; then
    echo "Usage: $0 <stations.txt> [<port>]"
    exit 1
fi

function clear_entries () {
    
    stty -F $PORT 115200 raw cs8 -cstopb -parenb -crtscts -ixon -ixoff
    exec {PORT_FD}> "$PORT"
    for (( i=1; i<=MAX_ENTRIES; i++ )); do
        cmd="#$i,ALL,0,FM"
        echo "Clearing entry $i"
        printf "$cmd\r\n" >&"$PORT_FD"
        sleep 0.2
    done

    exec {PORT_FD}>&-
}

function upload_entries () {


    # Format for the entries
    # group|freq(Hz)|<USB|LSB|AM|FM>|"comments"
    
    # Sample format to send
    # #59,ALL,10051000,USB
    
    sorted_entries=$(grep -v '^ *#' "$1" | sort -b -k1,1 -k2,2n  -t $DELIM ) 

    {
        # setup port
        stty -F $PORT 115200 raw cs8 -cstopb -parenb -crtscts -ixon -ixoff
        exec {PORT_FD}> "$PORT"
        
        let loc=1
        while IFS= read -r line
        do
            if (( $loc > $MAX_ENTRIES )); then
                echo "Only $MAX_ENTRIES entries supported"
                break
            fi
            
            entry="${line// }"
            IFS=$DELIM read -a cols <<< "$entry"
            
            group=${cols[0]}
            freq=${cols[1]}
            mode=${cols[2]}

            [[ -z "$freq" || -z "$mode" ]] && continue
            
            cmd="#$loc,ALL,${freq},${mode}"
            
            echo "Sending cmd:[$cmd] in group: $group" >&2
            
            ((loc++))
            
            printf "$cmd\r\n" >&"$PORT_FD"
            
            # sleep required to avoid corruption
            sleep 0.2
        done
        
        # Close the serial port
        exec {PORT_FD}>&-
        
    } <<< "$sorted_entries"


}

read -n 1 -p "Sleep is disabled in ATS Mini(Y/N)?" yn

[[ ! "$yn" =~ ^[Yy]$ ]] && { printf "\nAborting. Bye";  exit 1; }
   
echo

# Clear the entries first
clear_entries
echo "Cleared memory entries"

upload_entries "$STATIONS"

echo "Upload finished"

[acbits]

sample stations.txt file

# Format for the entries
# group|freq(Hz)|<USB|LSB|AM|FM>|"comments"
# Lines beginning with # are comments which are ignored
MARITIME| 6215000|USB|"Maritime"
MARITIME|  8291000|USB|"Maritime"
MARITIME|  2003000|USB|"Great Lakes"
MARITIME|  2670000|USB|"Coast Guard"
HFGCS|  11175000|USB|"HFGCS Daytime"
HFGCS|  15016000|USB| "HFGCS Daytime (secondary)"
HFGCS|  13200000|USB|"HFGCS Daytime (secondary)"
HFGCS|  8992000|USB| "HFGCS Nighttime"
HFGCS|  4724000|USB| "HFGCS Nighttime (secondary)"
HFGCS|  6712000|USB| "HFGCS Nighttime (secondary)"
MARITIME|  14300000|USB|"Maritime Mobile Service Net"
HAM| 14345000|USB|"National Traffic System"
HAM|  7200000|LSB| "40m HAM"
HAM|   7284000|LSB|"40m HAM Noon time Net"
HAM|  3913000|LSB|"80m HAM Liberty Net"
HAM|  3755000|LSB|"80m Ontario Phone Net"
HAM|  7153000|LSB|"40m Ontario South Net"
HAM|  7272000|LSB|"40m Transcontinental Variations Net"
HAM|  7255000|LSB|"ECARS (East Coast Amateur Radio Service)"
HAM|  3905000|LSB|"80m 7th Region Net"
HAM|  3916000|LSB|"75m The Tailgaters Net"
HAM|  3740000|LSB|"80m The Aurora Net"
 ISR| 2182000|USB|"International Search & Research"
 ISR| 3023000|USB|"International Search & Research"
ISR|  5680000|USB|"International Search & Research"
ISR|  8364000|USB|"International Search & Research"
 # ACARS requires 3 or 4 kHz BW
ACARS|5548000| USB| "ACARS  Nighttime Atlantic"
ACARS|8841600| USB| "ACARS daytime (8843 kHz)"
ACARS|8910600| USB| "ACARS Nighttime (8912 kHz)" 
ACARS|10081000|USB| "ACARS Global"
ACARS|13312000|USB| "ACARS daytime"
AVIATION| 3485000|USB|"MWARA North Atlantic (VOLMET)"
AVIATION|  6604000|USB|"MWARA North Atlantic (VOLMET)"
AVIATION|  10051000|USB|"MWARA North Atlantic (VOLMET)"
AVIATION|  13270000|USB|"MWARA North Atlantic (VOLMET)"
AVIATION| 3413000|USB|"Shannon| Ireland| Deep Night (VOLMET)"
AVIATION| 5505000|USB|"Shannon| Ireland| Nighttime/Late Evening (VOLMET)"
AVIATION| 8957000|USB|"Shannon| Ireland| Early Evening(VOLMET)"
AVIATION| 13264000|USB|"Shannon| Ireland| Daytime (VOLMET)"
AVIATION| 6754000|USB|"Canada (VOLMET)"
AVIATION| 15034000|USB|"Canada (VOLMET)"
AVIATION|  6577000|USB|"Northeast USA HF ATC"
AVIATION|  5550000|USB|"Northeast USA HF ATC"
AVIATION|  8906000|USB|"Eastern Atlantic ATC"
AVIATION|  5598000|USB|"Eastern Atlantic ATC"
AVIATION|  6622000|USB|"Gander/Shanwick (NAT-F) Evening"
AVIATION|  8864000|USB|"Gander/Shanwick (NAT-B) Day"
AVIATION|  11279000|USB|"Gander/Shanwick (NAT-D) Day(Very Active)"
AVIATION|  13306000|USB|"ARINC HF NAT-A"
AVIATION|  17946000|USB|"ARINC HF NAT-A"
AVIATION|  8846000|USB|"ARINC HF CAR-A"
AVIATION|  13291000|USB|"ARINC HF CAR-A"
BROADCAST|  17675000|AM|"RNZ"
BROADCAST|  15195000|AM|"NHK"
BROADCAST|  21500000|AM|"NHK"
BROADCAST|  17810000|AM|"NHK"
BROADCAST|  11960000|AM|"NHK"
BROADCAST|  3975000|AM
BROADCAST| 6030000|AM| "CFVP Calgary"
BROADCAST| 6180000|AM| "RN da Amazonia"
BROADCAST| 6115000|AM| "Radio NIKKEI 2"
BROADCAST|  7295000|AM
BROADCAST|  7415000|AM
BROADCAST| 7520000|AM| "WWCR Nashville"
BROADCAST|  9440000|AM|"NHK Germany"
BROADCAST|  9600000|AM
BROADCAST|  9700000|AM
BROADCAST|  9780000|AM
BROADCAST|  9790000|AM
BROADCAST|  9870000|AM| "Voice of Turkey"
BROADCAST| 9820000|AM| "Radio 9 DE JULHO (Brazil)"
BROADCAST|  9835000|AM| "RTM Sarawak FM (Malaysia)"
BROADCAST|  11995000|AM
BROADCAST|  13720000|AM
BROADCAST|  13660000|AM
BROADCAST|  13670000|AM
BROADCAST|  11625000|AM
BROADCAST|  11860000|AM
BROADCAST|  12060000|AM
BROADCAST|  13840000|AM
BROADCAST|  15720000|AM
BROADCAST|  15245000|AM
BROADCAST|  13760000|AM
BROADCAST| 6120000|AM|"Radio France International"
# Enable FT8 entries by removing the # at the front.
#FT8|1840000|USB|FT8
#FT8|3573000|USB|FT8
#FT8|5357000|USB|FT8
#FT8|7074000|USB|FT8
#FT8|10136000|USB|FT8
#FT8|14074000|USB|FT8
#FT8|18100000|USB|FT8
#FT8|21074000|USB|FT8
#FT8|24915000|USB|FT8
#FT8|28074000|USB|FT8

[acbits]

If I increase the sleep to 1 second, the errors gets reduced, but entry #1 is still missing.

Does the ATS Mini take a long time to flush the entries to flash memory?