Building images for ramips - NETGEAR EX6120 fail. Using attendedsysupgrade as well as using the website (firmware-selector)

Building images for ramips - NETGEAR EX6120 Packages: arp-scan arp-scan-database base-files busybox ca-bundle dawn dnsmasq dropbear firewall4 fstools fwtool getrandom hostapd-common iw iwinfo jansson jshn jsonfilter kmod-cfg80211 kmod-crypto-acompress kmod-crypto-aead kmod-crypto-ccm kmod-crypto-cmac kmod-crypto-crc32c kmod-crypto-ctr kmod-crypto-gcm kmod-crypto-gf128 kmod-crypto-ghash kmod-crypto-hash kmod-crypto-hmac kmod-crypto-manager kmod-crypto-null kmod-crypto-rng kmod-crypto-seqiv kmod-crypto-sha256 kmod-gpio-button-hotplug kmod-leds-gpio kmod-lib-crc-ccitt kmod-lib-crc32c kmod-lib-lzo kmod-mac80211 kmod-mt7622-firmware kmod-mt76x2 kmod-mt7915-firmware kmod-nf-conntrack kmod-nf-conntrack6 kmod-nf-flow kmod-nf-log kmod-nf-log6 kmod-nf-nat kmod-nf-reject kmod-nf-reject6 kmod-nfnetlink kmod-nft-core kmod-nft-fib kmod-nft-nat kmod-nft-offload kmod-ppp kmod-pppoe kmod-pppox kmod-rt2800-lib kmod-rt2800-mmio kmod-rt2800-soc kmod-rt2x00-lib kmod-rt2x00-mmio kmod-slhc libblobmsg-json libiwinfo libiwinfo-data libjson-c libjson-script libmbedtls libmnl libnftnl libnl-tiny libubox libubus libuci libuclient libucode logd luci luci-app-attendedsysupgrade luci-app-dawn mtd netifd nftables-json odhcp6c odhcpd-ipv6only openwrt-keyring opkg ppp ppp-mod-pppoe procd procd-seccomp procd-ujail swconfig ubox ubus ubusd uci uclient-fetch ucode ucode-mod-fs ucode-mod-ubus ucode-mod-uci urandom-seed urngd usign wireless-regdb wpad-openssl base-files busybox ca-bundle dnsmasq dropbear firewall4 fstools kernel kmod-gpio-button-hotplug kmod-leds-gpio kmod-mt76x2 kmod-nft-offload kmod-rt2800-soc logd mtd netifd odhcp6c odhcpd-ipv6only opkg ppp ppp-mod-pppoe procd procd-seccomp procd-ujail swconfig uci uclient-fetch urandom-seed urngd

Package list missing or not up-to-date, generating it.

Building package index...
Downloading https://downloads.openwrt.org/snapshots/targets/ramips/mt7620/packages/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_core
Downloading https://downloads.openwrt.org/snapshots/targets/ramips/mt7620/packages/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/base/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_base
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/base/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/targets/ramips/mt7620/kmods/5.15.96-1-3030a45aec28121bb030619f7ca6e0fd/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_kmods
Downloading https://downloads.openwrt.org/snapshots/targets/ramips/mt7620/kmods/5.15.96-1-3030a45aec28121bb030619f7ca6e0fd/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/luci/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_luci
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/luci/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/packages/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_packages
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/packages/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/routing/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_routing
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/routing/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/telephony/Packages.gz
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/openwrt_telephony
Downloading https://downloads.openwrt.org/snapshots/packages/mipsel_24kc/telephony/Packages.sig
Signature check passed.
Downloading file:packages/Packages
Updated list of available packages in /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/../../../../../../../../../../../home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/dl/imagebuilder
Downloading file:packages/Packages.sig
Signature check failed.
Remove wrong Signature file.
Pseudo file "dev" exists in source filesystem "/home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/dev".
Ignoring, exclude it (-e/-ef) to override.
4828+1 records in
4828+1 records out
2472258 bytes (2.5 MB, 2.4 MiB) copied, 0.014665 s, 169 MB/s
13113+1 records in
13113+1 records out
6714308 bytes (6.7 MB, 6.4 MiB) copied, 0.0423025 s, 159 MB/s
padding image to 008c3000
bash: line 1: 8: Bad file descriptor
Failed to open firmware file
sha256sum: /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/linux-ramips_mt7620/tmp/openwrt-19bf2baedaa3-ramips-mt7620-netgear_ex6120-squashfs-sysupgrade.bin: No such file or directory
cp: cannot stat '/home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/linux-ramips_mt7620/tmp/openwrt-19bf2baedaa3-ramips-mt7620-netgear_ex6120-squashfs-sysupgrade.bin': No such file or directory
4828+1 records in
4828+1 records out
2472258 bytes (2.5 MB, 2.4 MiB) copied, 0.0156637 s, 158 MB/s
13113+1 records in
13113+1 records out
6714308 bytes (6.7 MB, 6.4 MiB) copied, 0.0423475 s, 159 MB/s
padding image to 008c3000
bash: line 1: 8: Bad file descriptor
mkchkimg: Netgear CHK writer - v0.1
mkchkimg: Cannot open /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/linux-ramips_mt7620/tmp/openwrt-19bf2baedaa3-ramips-mt7620-netgear_ex6120-squashfs-factory.chk: No such file or directory
make[3]: *** [Makefile:231: /home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/linux-ramips_mt7620/tmp/openwrt-19bf2baedaa3-ramips-mt7620-netgear_ex6120-squashfs-factory.chk] Error 1
make[2]: *** [Makefile:204: build_image] Error 2
make[1]: *** [Makefile:142: _call_image] Error 2
make: *** [Makefile:258: image] Error 2

This is where the script starts derailing:

Signature check failed.
Remove wrong Signature file.
Pseudo file "dev" exists in source filesystem "/home/aparcar/asu/worker1/cache/SNAPSHOT/ramips/mt7620/build_dir/target-mipsel_24kc_musl/root-ramips/dev".
Ignoring, exclude it (-e/-ef) to override.

And it continues crashing from there onward.

Start by reproducing the ramips/mt7620 NETGEAR EX6120 build through attendedsysupgrade or firmware-selector, then inspect the image build around Makefile:231 and the logged package-signature and bad-file-descriptor failures. Done means the build completes and produces both the sysupgrade.bin and factory.chk firmware files.